First things first. We now have a proper PvP endgame for a PvP game. PvE endgame to a PvP game didn't make much sense.
Full details on the changes can be found here.
I like that I no longer have to try to coordinate hundreds of people across multiple instances to make sure I didn't just waste 3-4 hours pushing the campaign forward to be denied because one instance lost one stage of the city public quest. It's much easier to coordinate hundreds of players when you can actually see what they are doing and help them out. Once the city is cracked open, it's my warband against the enemy warband, and may the best win.
I do like that defenders actually do get a shot at the best stuff in the game. It appears that this will truly be hard mode for getting the gear though. On the other hand, if defenders are at too much of a disadvantage, they may not show at all, and then we're back to the same problem we have now. Stage 1 is heavily slanted towards the invaders for example. If the invaders can manage one wipe of the defenders early, it looks like they'll be able to take the first two objectives easily, especially if they get lucky and leave the enemy with a 30s respawn.
Stage 3 just looks cool. Instead of NPCs being the raid bosses, players are the raid bosses. This was already a trend in other games (like LotRO and Aion). I've got my final judgment on it reserved until I play it and it's tweaked. I think it could be awesome though. I prefer fighting actual intelligence to artificial intelligence anyway. If the champions are too strong, everyone else will die too quickly and it will just be the champions fighting each other. If too weak, it'll be zergball on the champ healers. Both are equally lame. In an ideal situation, the Champions will need the non-Champions to protect them from getting zerged down and the non-Champions need the Champions to prevent from being overpowered by enemy Champions. It'll require testing. Wards do play a role in this though. If one side doesn't have Excelsior Wards and the other does, it won't be pretty for the side that doesn't. It should be that way in my opinion. They don't really need the Sovereign anyway if they lack the Excelsior Wards.
Stage 2 looks kinda blah, but again, it'll require playing it to find out. It could be awesome. It could also be a snorefest escort quest.
So hopefully, it'll be coming soon to a Public Test Server near you. Come on out and leave your feedback.