Offering one player choices of weapons and not offering it to another gives an advantage to the one that has the choices.
WHAT? Offering to one player but not another? Are you seriously fucking retarded? They are available for EVERYONE to unlock. They aren't even difficult to get, nor do they take much time to get.
Quake, Quake 2, any of the old games...players start out with basic weapons and you have to figure out where those weapons are and collect them. For a new player, that can be a daunting task because you usually have the veteran players camping them or have timed the respawn of the good weapons. There is little difference in the fundamentals here, except one is unlocked permanently, the other you have to keep going back for constantly.
I've played dozens of multiplayer games where other players have access to things that other players do not. CoD4, CoD WaW, BF2, etc and pretty much ever MMO ever made. People praised Infinity Ward for adding leveling and weapon/item unlocks to CoD4. Now Valve does something similar, and the same fucking asshats that rip on Valve no matter what they do, are the same ones ripping on Valve for weapon unlocks in TF2.