Rage is generated by taking and dealing damage. However, 2.0.1 introduced rage normalization, which changed the way dealing damage would generate rage. Previous to that change, it was effectively linear - the more damage you did, the more rage you got. (I realize this is an oversimplification.) Now, this would have been broken if it had continued into TBC, I'm not arguing that rage didn't need to be normalized. However, when 2.0.1 rolled out, rage normalization was set too low, leading to many warriors (especially tanking warriors, with their higher defense and damage mitigation, meaning that they weren't generating as much rage from taking damage) being literally starved for rage. A warrior starved for rage can't tank effectively, and combined with a lack of sustainable AoE tanking options (switching stances to Battle to pop thunder clap was at best a workaround, since just switching stances costs you rage, and rage is what we were starved of) you saw a decline in warrior tanks. During the crucial period between the launch of the game and until March of 2007, in fact, warriors almost became obsolete as tanks. Groups prefered druids and paladins as tanks in the new five man instances, as they didn't have to stand around and wait, and wait, and wait for the rage-starved warrior tank to finally generate enough rage to get solid aggro, a problem exacerbated by the combination of having to tank three or more mobs fairly often and having no real way aside from tab targeting and sunder/devastate spamming to hold aggro on them. (The high rage cost of Shield Slam made it fairly hard to use in these situations.)
Luckily, in patch 2.0.10 this was to some degree fixed. The Rage Normalization equations were adjusted upwards to allow for more rage generation (I believe these are the current formulas), and several smaller buffs were implemented (1% crit increase, thunder clap in defensive stance, a buff to Commanding Shout) that made tanking easier in the new instances. However, thanks to the Arenas being implemented at the same time, a lot of warriors seemed to have given up on tanking by this point. If anything came close to souring me on the game to the point where I would have stopped playing, it was the drastic negative effects that I witnessed, not only on my own warriors but on warriors I'd known for more than a year previously. Watching them stop tanking, or worse, stop playing entirely over this issue. The ones who stuck it out showed that common trait of stubbornness that seems to form the bedrock of all warriors. We're ornery cusses, I guess.
Warrior dominance in arenas has been commented on before. We're certainly a very common presence in there. But rather than seeing this as a sign of warriors being overpowered I've always viewed it as a consequence of the opening months of 2007. Quite frankly, druids and paladins were finally viable tanks for the new instances, which was fine and good. Nothing wrong with that. However, for those crucial weeks when the rush of 60's heading into Outland were first looking for tanks, warriors weren't. This is easily seen reflected in the changes from patch 2.0.10: warriors were behind in rage generation (since, unlike a bear druid, they had higher total mitigation meaning that they couldn't generate rage as quickly) and their inability to provide much in the way of snap group aggro meant that groups were preferring to use the new tanks which didn't force them to wait and wait and wait for aggro to be established. Since we know that warriors were and still are one of the most played classes in the game, what were they expected to do? Were all warriors going to reroll druids and paladins over that six week or so period when they simply couldn't tank nearly as effectively against the trash in the new instances?
No, they didn't do that. Instead, they went out and PvP'd. They ran BG's, they did world PvP in Halaa, and as they hit 70 they formed arena teams. Since the rage normalization effect wasn't nearly so pronounced for non-tanking warriors, they were still quite capable in PvP, and by the time the situation was addressed the domino effect couldn't be stopped. Meanwhile, warrior supremacy as single target tanks still hasn't gone anywhere, meaning that a lot of tanking druids and paladins got disenchanted and stopped doing it when bosses made hash of them (a lot stayed, upgraded their gear, and are stellar tanks now) so we have the current situation where DPS and PvP warriors don't see a need for them to tank, there aren't enough druid and paladin tanks (each class being about half as populous as warriors) to make up the difference, and those few warriors who stuck with the class through the rage normalization drought usually end up tanking for their guilds instead of PuG's. So yes, I credit the rise of the PvP warrior and blame the tank shortage on rage normalization, specifically the mistakenly low original rage normalization formulas.
It hasn't been all bad this year... clearly, patch 2.0.10 fixed a lot of problems... but aside from Flurry being nerfed in 2.1.0, the weird back and forward changes to Sword spec, and the changes to the warrior arms and fury trees in 2.3.0 (well, okay, there was also that sweet change to Devastate meaning that my tanking warriors could finally take Sunder off of their bars) warriors haven't changed all that much. We got new talents and abilities back at the beginning of the year like Victory Rush, Spell Reflection and Intervene, but those haven't been altered or buffed much at all. Warriors still seem to believe that the 41 point talents in both the Arms and Fury trees aren't all that great for PvP, although Rampage seems to be getting some love from DPS warriors in PvE at least. There were several changes later in the year that were very nice (Taunt getting benefits from hit rating, Tactical Mastery increasing threat for the signature instant attacks from the Arms and Fury trees when in Defensive Stance to try and help non-prot tanking, probably to encourage more PvP and DPS warriors to try tanking for PuGs) but nothing earth shaking. Generally, since March, warriors haven't changed much at all. Patch 2.3.0 saw some confusing juggling of talents and a few changes to how disarm works and introduced the Expertise mechanic, the biggest change to the class since 2.0.10.
It's hard to properly rate how things like the new Blacksmithing weapons and armor affected the warrior class. Mace Specialization in PvP would never have been so attractive without the crafted maces, that's certain, as Stormherald's popularity shows us. Warriors as such a gear dependent class can only benefit from 'sure' upgrades, that is to say, upgrades one can quest for, PvP for or craft rather than having to hope for a random drop and then either spending DKP furiously or hope a dice roll goes their way. Certainly in 2007 it's been easier than ever to get reasonable gear for your warrior, and the move of Arena Season 1 gear to the honor system has been the icing on the cake for warriors looking to get equipment with the least rigid investment of time. Both the craftable gear and the PvP gear affects other classes as well, of course, which is why it's hard to rate how warriors were affected by it, but in general I'd have to say they were positive changes to the class.
Now that we're moving into 2008, what I'd most like to see is the last lingering bad effects of the original poor implementation of rage normalization swept away - more warriors tanking and willing to tank would be a positive change, in my opinion. PvP can continue as it is, and the DPS warrior will always be a factor, but warriors need to step it up and tank more often to show themselves that they've finally recovered, that warriors do in fact have all the tools now to tank anything in the game. Those of us who were burned, come on back to tanking, it's actually fun again. If you're that special kind of masochist who likes tanking, anyway.
So that's my year in review. Feel free to use the comments to discuss the big changes of 2007, including the ones I just know I missed.