Well I dunno if any of you have heard of the news regarding PvP in the expansion, but they are completely doing away with the honor system. No ranks, no more honor decay, none of that bs.
The highlight as far as pvp is concerned will be the new Arena-style pvp battlegrounds. What you do is, come level 70 you form a team specifically for competition in this arena. This team functions exactly as a guild, except that it is more in line for pvp. There will be different brackets, such as 2v2, 3v3, and 5v5(not sure how high it will go). There is even talk about having leagues and seasons, much like real life sports and such. I honestly can't wait for this feature more than anything out of the expac.
Oh, and did I mention REAL world pvp? There will be specific towns in Outland which start out neutral, but can be captured by either faction. Once this town is fully captured, that faction is free to use its vendors, get quests and items, repair, etc. However, the opposing faction can and will take this town, using their own NPCs and even ARTILLERY
. So finally they are putting the war back into Warcraft. I can't wait.