Those slippery scoundrels of stealth are also masters of movement control. First of all, Rogues can disappear. Moving around undetected is a big step towards freedom of movement, allowing Rogues (and Druids, too, of course) to approach their opponents with impunity. While Stealth reduces movement speed by 30%, the Subtletly talent Camouflage lessens this slowing effect to only 15%. Rogues also have Vanish, allowing them to return to stealth even during combat in order to flee or execute moves that require Stealth.
Rogue movement was buffed in Patch 2.3 with the revision to the Assassination talent Fleet Footed, increasing movement speed up to 15% from an anemic 8%. It was a much needed change as many players who would PvP enchanted their boots with an increase to movement speed. Fleet Footed also increases snare resistance by a good 10%, which doesn't hurt one bit. Sprint is a baseline ability that allows them to, well, sprint 70% faster for 15 seconds every five minutes (I forgot to mention that Druids also have this in Cat Form as Dash. Have I mentioned that Druids are incredibly mobile? Well, they're incredibly mobile.). It's great for catching up with enemies to deliver the killing blow or, just as often, to escape from it -- Improved Sprint is a Combat talent that also frees the Rogue from snares and bonds.
Rogues also have one of the coolest moves in the game in the form of the Subtlety talent Shadowstep. Similar to the Mage ability Blink, Shadowstep transports the Rogue from one place to another instantly provided the Rogue has an enemy targeted. It can even be used to interrupt spells with some timing. Shaman casting Lightning Bolt at you? Shadowstep and deal some hurt from behind. Of course, we mustn't forget Cloak of Shadows, the Rogue's own version of Divine Shield. It removes harmful spell effects, including most forms of CC as well as magical snares.
As far as limiting the movement of one's opponent goes, how does keeping them in place sound? Before Warriors went around waving their Lolheralds and mace specs, Rogues were and are still the true masters of the dreaded stun lock. With their plethora of stuns -- from Cheap Shot to Kidney Shot to the Combat talent mace specialization -- Rogues can prevent opponents from moving. Heck, from doing anything at all! In between stuns, Rogues also have Gouge and Blind. The change to Blind making it a Physical effect rather than a Poison has made it even more formidable. Patch 2.3 also made it cheaper to cast... dirt cheap. Out of combat, Rogues annoyingly abuse Sap, stopping even mounted opponents in their tracks. If that doesn't work, Distract works very nicely in sending opponents back in your direction. More sinister Rogues (and there are plenty) sometimes even send enemies off cliffs in the Battlegrounds with a well-timed and well-placed Distract on mounted targets.
Of course, as masters of poisons, one Rogue staple is Crippling Poison, which slows opponents down to a glacial 70%. Even at a 30% chance to apply -- and Rogues have talents that improve upon that -- their blazing attack speed make application a pretty sure thing. (Thanks Ashwin and Sal!)
Finally, there's Deadly Throw, which cemented thrown weaponry in a Rogue's arsenal. A primarily PvP-only skill, Deadly Throw is excellent for finishing runners and has surprised more than one fleeing opponent who thought that Rogues were only good at close range. Although its primary benefit is the snare, Deadly Throw can deal a fair amount of hurt and with PvP gloves can also interrupt spellcasting. You can almost hear the words "FINISH HIM!"
With all the current uproar about Shamans, it probably doesn't help to state that Shamans count among the classes with limited mobility. Barring the speed-enhancing Ghost Wolf, which takes three seconds to cast -- down to one if you have the talent -- Shamans have no natural way to close or widen the distance between themselves and their enemies. Before you scream "Bam! Frost Shock!", keep in mind that Shamans have no means to remove snares, whether Physical or Magical in nature. What Shamans do have are some of the coolest (note how I didn't say best) snares in the game -- yes, Frost Shock, and Earthbind Totem. Frost Shock is great in that it deals damage as well as slows down opponents, and its slowing effect lasts longer than the spell's cooldown. This means that, in theory, a Shaman can keep his enemy slowed all the time. It's also an instant cast spell... and, you guessed it, instant cast is king.
Earthbind Totems can be improved with the second tier Elemental talent Earth's Grasp, which can be handy when slowing down hordes of adoring fans or angry mobs (more likely). On the downside, Earthbind Totems only have 5 health, making them extremely easy to eliminate unlike a Hunter's Frost Trap which sticks around even after the Hunter is dead. Neither Frost Shock and Earthbind Totem is spammable, the former with a 6 second cooldown and the latter with 15, so classes able to remove these slowing effects have a window within which to catch or flee from the Shaman. Shamans also notoriously lack any form of crowd control, making escape from movement-limiting opponents a tall order.
On a good note, Shamans have Purge, which is one of the best PvP spells in the game. Purge, used properly, can be key to limiting an opponent's movement by removing movement-protecting or -enhancing buffs such as Blessing of Freedom. Although nerfed somewhat in Patch 2.3 because it destroys itself after absorbing any spell, Grounding Totem works as a form of protection against magically cast snares and CC -- before they're cast, that is. It's not much, but it's what Shamans have got, and the best ones use it to full effect.
More than a few PvPers have had first hand experience with a Warlock's frustrating use of Fear. These diabolical demon-lovers have access to more fear effects, too, which allows them to set some distance between themselves and their opponents. The Affliction talent Curse of Exhaustion is a key PvP spell that is a Warlock's one of the few defenses against certain plate-wearing, Fear-immune characters. Although it takes up the slot of one Curse effect, for a class that has no real means of countering snares, it's often well worth the application.
Warlocks also have Death Coil, which is an instant cast horror effect that they can use in a pinch to escape from berserking opponents. Note that it is a horror effect -- a change implemented in Patch 2.1 -- and not a Fear effect, allowing it to work through Fear immunities. Of course, they also have Howl of Terror, which when specced-properly can also be cast instantly, and affect multiple opponents at the same time. Of course, as these types of spells go, opponent movement becomes erratic and fleeing enemies are usually driven far away from the Warlock. It's not so much control as chaos, but it's what Warlocks thrive on as they have many channeled spells that can benefit from enemies running around like headless chickens.
Destruction also gives access to stuns and disorienting effects, such as Pyroclasm. Unfortunately, Rain of Fire and Hellfire are both channeled, and Soulfire is a 6-second cast (4 seconds with the right talent) spell, so it's not as compelling a talent as it sounds like. On the other hand, there's Aftermath, which adds a chance to daze opponents to all Destruction spells, and the very-nearly instant cast 41-point talent Shadowfury, which stuns multiple opponents at once.
Of course, we mustn't forget the Warlocks' tools of malice and mayhem -- their pets. Two, in particular, offer a form of crowd control which can limit opponents movements long enough for the Warlock to position herself better for combat. The 41-point Demonology talent Felguard can charge with the Warrior-like Intercept, which is usable every 30 seconds. The Succubus uses less brutal methods to keep Warlock prey in place. Seduction is a staple spell that allows Warlocks to CC two enemies at once and, presumably, kill a third. Warlocks are just nasty that way.
Finally, we have the fearsome Warrior, quite possibly the most well-represented class in Arenas. Warriors have limited choices with regards to their own mobility, having no snare-removal, but have a plethora of abilities that can keep their victims in place. Warriors usually Charge into Battle, temporarily stunning their targets, followed by the ridiculously spammable Hamstring, a cheap (10 rage) strike that has no cooldown. Hamstring is also a Physical effect -- making it hard to remove -- elevating it as one of the best snares in the game.
When opponents do manage to get away, Warriors use Intercept, arguably their most important skill. Intercept ensures that opponents are always within reach of their massive swords or axes. Because of the stun component, Intercept is also one of the Warrior's ways to interrupt spellcasting. Although unlikely to be used in PvP because it requires a shield and the Warrior to be in Defensive Stance, Shield Bash is another way to interrupt spells. It is mentioned here because of its minor daze component in Rank 4.
Of course, what is a Warrior who doesn't shout? Warriors have one of the more interesting AoE fears in Intimidating Shout, which fears 5 nearby (10 yards) enemies while incapacitating the Warrior's target for 8 seconds. This is extremely usable as a means to control movement, even fleeing opponents as it roots the target in place instead of sending them scurrying away like madmen. Of course, any damage will break the effect, but if it's a 6k Execute, who cares?
Arms Fury (Thanks, Souvlaki and Heracles!) also has the talent Piercing Howl, which dazes all enemies within 10 yards of the Warrior for 6 seconds. Warriors may not have any anti-snare abilities, but enough abilities to keep enemies close. Furthermore, Warriors are also notoriously resilient against fear and/or incapacitate effects with Berserker Rage, Recklessness, and the Arms talent Death Wish. Rogues would be foolish to try and sap Warriors guarding flags in Arathi Basin, for example (it still happens quite a lot). The talent Second Wind also makes up for when the Warrior is stunned or rooted. It's not an anti-snare, but it helps ensure that the Warrior is ready for some payback when the effect breaks. EDIT: Reader Heracles mentions Conussion Blow, a 5-second stun 21-points deep into Protection. Thanks, Heracles!
Did I miss anything? I'm sure there are some abilities and clever usage of talents that I've missed out on. That said, even with movement control abilities -- or lack thereof -- all players can take advantage of items and consumables to help them in combat. Perhaps the first item I'd recommend any serious PvP player to get would be the Alliance or Horde PvP trinket. Homogenized to free the owner from all types of crowd control, snares, or root effects, these trinkets are the single most important PvP item that can be purchased with Honor. If you were to buy only one thing with Honor points, buy the trinket. It is currently the only effect in the game that can counter the ridiculously powerful Cyclone.
Potions are also an excellent resource to ensure unrestricted movement. Free Action Potions are a cheap, easy-to-make consumable that help prevent stuns and movement-impairing effects. Note that it's a preemptive potion, so it should be taken before engagement or in between control effects. Its older brother, the Living Action Potion, on the other hand, can be taken while stunned or slowed but are considerably more expensive to produce.
Enchanting also offers something that serious PvP players would be remiss not to apply. Enchant Boots - Surefooted is notable because it's the only Enchantment that requires Primal Nether. A PvP staple, Surefooted is a stacking resistance that works together with Enigmatic Skyfire Diamond. Both are also tailored for melee classes, as the Surefooted +hit bonus does not apply to spells and the aforementioned Meta Gem gives attack Critical Strike. On the other end of the spectrum, there is Boar's Speed and Cat's Swiftness, both considerably cheaper to obtain as neither require Nethers or Void Crystals. The former is good even for casters in PvP as it adds Stamina while the former is tailored for Rogues or Hunters. This enchantment does not stack with other speed-enhancements such as Meta Gems or talents, so the choice is between these boot enchants or any of the three Swift Skyfire Meta Gems. Many Meta Gems provide PvP benefits, particularly resistance to stuns, which help in maintaining free movement. Some old world items such as the quest reward Nifty Stopwatch or for mounted speed the sentimental Carrot-on-a-Stick help improve PvP on occasion.
Of course, Orcs have the passive 15% stun resistance in Hardiness, which is a boon in PvP. Conversely, Tauren can stun enemies with an AoE stomp, which is excellent for escaping or preventing escape. Undead have Will of the Forsaken, which breaks several forms of crowd control. Not to be outdone, Gnomes are natural Escape Artists who are able to free themselves from bonds every 1.75 minutes, another indispensable ability in PvP. Needless to say, movement is important in PvP. If you want to have fun while doing it, make sure you exhaust all avenues to ensure that you're free as a bird.
Zach Yonzon writes the weekly PvP column The Art of War(craft) between renovating their house and cleaning up after his fast-growing three month-old daughter, Zoe. He promises to get his column out on time next week... that should be Monday.