While Blizzard has made some steps to homogenize the playstyle of the Horde and Alliance a bit with the whole Paladin/Shaman swap, they've also done a bit of experimenting in the Burning Crusade with allowing people to make choices about certain paths, namely the Aldor and Scryer factions.
While patch 2.4 has bought as an "end" to the Aldor/Scryer rivalry lore-wise, the mechanics remain the same: You cannot enter the other side's tier without being attacked, you can't use the other side's bank, and the item and shoulder enchant vendors will still only sell to those with proper faction. In addition, there's a new twist to the sides from this patch: At exalted reputation with the Shattered Sun Offensive, you can purchase 4 different neckpieces that have seperate bonus that depending on whether you're Scryer or Aldor.
Shattered Sun Pendant of Acumen is a spell DPS necklace which has a chance to give you 120 spell damage per 10 seconds if you're Aldor or cast an Arcane Bolt for an extra 350 damage or so if you are Scryer. In what would seem to a bug, the proc works on almost any action, which means if you have an enemy targeted while buffing yourself, you can accidentally pull them with an Arcane Bolt proc.
Shattered Sun Pendant of Might is a physical DPS necklace which has a chance to give you 200 attack power for 10 seconds if you're Aldor or throw out an Arcane Strike (similar to Acumen's Arcane Bolt) if you are Scryer. The Scryer proc is currently a pain since it can work off Sap, thus canceling out the Sap immediately.
Shattered Sun Pendant of Resolve is sort of a melee/tank hybrid type of necklace which has a chance to give you 100 dodge rating for 10 seconds if you are Aldor or 100 expertise for 10 seconds if you are Scryer.
Shattered Sun Pendant of Restoration is a healing necklace which has a chance to give you 220 healing and 74 spell damage for 10 seconds if you're Aldor or cast an instant heal for 618-682 damage if you are Scryer. It should be noted that the procs will work off any tick of a HoT as well as long as actual healing is done.
So while these necklaces all look pretty sweet at first glance, there's been some complaints that the Aldor procs are all clearly superior to the Scryer procs in almost all situations. In other cases, some Aldor are saying they wish they had access to that sweet expertise proc off the resolve pendant.
I don't mind so much that there's differences between the factions. I have 3 70s, one of which is Scryer and two of which are Aldor, and I've definitely seen the differences between the factions. On the Scryer tier, I step out of the Inn, and I have a tradeskill vendor a few feet to my right and a repair vendor a few feet to my left. On the Aldor tier, I have to run over to the other side of the tier to repair, and have to fly down to Lower City if I need to buy some Rune Thread. There's also a definite advantage to going Scryer as a spellcaster so you can score the very sweet Scryer's Bloodgem. Paladin and Warrior tanks might end up going Aldor for the Vindicator's Hauberk. So in this case, the necklace is just one more thing to look at when making a choice.
The problem comes in when you can't make that choice any longer. Many 70s who are now at exalted or grinding slowly towards it have made their choice and are now max exalted with their chosen faction, and the lowest dregs of hated with the other. So for them to now see these necklaces and decide they'd rather have the other side's procs isn't that clearcut of a choice anymore. They'd have to go back and do some serious grinding. In that case, it's a little bit difficult to expect them to just accept that they're Aldor and the Scryer proc on their necklace is a bit better for their chosen play style, or vice versa. I'd say this has been an interesting mechanic in concept, but in execution, it may be too much to ask that people who have already made a choice before they even knew the necklaces would exist be made to deal with it.
In the end, I hope we really do get less into Aldor and Scryer types of splits and into the classic Horde and Alliance splits when it comes to Northrend. At least then the choices (besides that silly Seal of Blood) are mostly cosmetic and lore based. I'd really rather not have to choose whether to ally with the Scarlet Crusade or the Argent Dawn in Northrend. After all, everyone knows the Argent Dawn rules supreme.