3rd person is kinda considered a cheat in the world of action simulation games because you can see around corners and over objects you shouldn't be able to.
Think about Call of Duty modern warfare 2 for instance. Even though its not a simulation style game, they have two 3rd person modes of gameplay, neither of which are hardcore or have that many people playing them. Also at least for me, they just aren't as fun in 3rd person.