The trend seems to be that in a game based around the stealth/sneaking/agility (e.g. Splinter Cell, Assassin's Creed), games in which you don't have the option to choose to play differently, the agility/stealth guy is ridiculously good.
However, in games where you can choose to play with different skills, the agility guy usually stinks in direct combat, which you always wind up getting in to. Sure, in games like KOTOR I/II, Mass Effect, etc., you *can* play the stealth guy, and you *can* beat the game, but there are really only two outcomes: One, the way the game is played is so similar between the classes that it really doesn't matter which one you pick, or two, the game is undeniably biased towards the lowest common denominator Beefy McGee strength characters.
And what about the first person shooters? Imagine in Call of Duty you're standing up on a building when someone playing as an assassin runs up the wall, stabs you in the neck, and throws your corpse off of the side.
... Actually, Infinity Ward should get on this pronto.