I've been playing the trial as well. I'm level 10 and had to stop myself from leveling. The trial only lets you hit level 14. Which is nice, I guess. You get to see what your travel power will act like and how it works. However, 14 is hardly far enough into the game to get a feel for it. 20 would be a better number. I think that's when you can actually PvP.
I can't really comment on Aion, but I've heard enough to know it's probably not for me. I hear it gets very grindy. I also hear the same thing about CoH/V. However, in CoX I find it interesting. A game where gear doesn't matter for a change. I find it to be refreshing not to have to worry about the constant grind of end-game content.
Either way, I have a Villian on the Justice server.
City Of Heroes/Villains isn't very grindy at all. Also, about the AE content, they nerfed the exp on it, its a little bit less exp or at best, the same exp as normal missions. They are thinking about making AE missions give no exp so yea. Less social? Please, CoH/V is still one of the most socially active mmo's in terms of teaming up, hanging out with people in game, social events, etc. It just depends on what server you play on.
Anywho, about endgame, its pvp, badge hunt, grind for set pieces...same as any other mmorpg, so that cannot be considered a negative since all mmo's share that. Some of the AE missions are really fun and worth doing even if your not exp grinding. They got some high profile people/groups to make missions in the game. (Rooster Teeth, Seth Green, etc)
Mission : Go here and either steal this or kill this.
Go in bash some people with powers and look at the newspaper some more.
To me i found it painful but my friends love it and still play it, your downloading the trial so it cant hurt at all.
Not saying its a terrible game, but the combat system and features didnt suit me. Another reason why ive found crap all to do most of the time unless playing in the early hours is, im australian. Sooo yeh WoW is one of the only mmo's ive found that been extremely active around the times i usually log on.