F2P would work fantastic in a perfect world, but generally it results in the devs pushing the cashgrabbing as far as they can to make th emost amount of money (see: TF2's experimenting with crafting recipes and time between store release and drop release). Generally, a fully paid multiplayer game is much better than a F2P game.
That being said, F2P is kind of a necessary evil; tons of games, including TF2, have to switch to the model to attract new players to an older game, since a multiplayer game with too few players is a dead game. F2P is essentially the online multiplayer's iron lung, in both the good- and bad ways