I really enjoyed bf3. Then I quit playing in favor of Skyrim for a few months and never got back in to it. 2142 was by far the last great bf game, but it had its launch issues too. Bf2 was probably the only one in the series that was complete at launch.
I actually think the map design in Bf3 was better than Bf4. Don't get me wrong, I'm really enjoying the new layouts and learning how to play them, Metro was probably one of the most fun Infantry maps I've played. As for actually liking BF4 as a game, it's good enough until something better comes out. To me, it feels like bf3 with better graphics, more destructibility, worse optimized, and many more bugs.
Maybe we will see 2143 here soon.
I always liked the way Aion intended to balance the 2 factions in their servers early in Aion's US lifecycle. The third faction were npc's and could be controlled by GM's. I never thought the npc faction was strong enough to really sway the game one way or another. Eventually, one side or the other would have an exodus causing major imbalance and long leveling times prevented new players from really helping their faction. Pretty much killed the game for me.
Bethesda is going to have their hands full trying to keep pvp and "winning" beneficial without stalling player progression for the "losing" sides. Like a previous poster said, it will more than likely be 2v1 against the strongest faction.