I would prefer a multiplayer game to be "slow". It should be more methodical than just running around. I haven't found the perfect online multiplayer yet. This may sound stupid, but killing someone should be as much about luck as it is skill. I've shot a paintball gun before and have fairly accurate aim. But I'm not a professional player. However if you put me in a building with a professional player starting off on different floors, I should have just as good a chance of shooting him as he has of shooting me assuming I'm not running through the halls like some butt-monkey. There should be a little bit of randomness to it.
Me and 5 of my friends played Deathmatch on SWAT 3 one time. It was great. We were inside a hospital. It was funny when you came around a corner and saw one of the others trying to sneak down the hallway all careful only to get popped in the back by me. Everything online wants to go at 100mph.
I will forgive Team Fortress 2 though (greatest game ever).
UT and Quake were methodical and you had to think fast, but you also had to do this while moving fast. Twitch style games like that aren't for everyone. It takes a different type of skill than playing in semi-tactical style shooters such as Call of Duty or Battlefield.