It's an interesting idea and has some merit but there are a couple things that will keep this from happening.
Firstly, EA has a clause in their terms of service that actually prohibits server owners from restricting weapons/classes on BC2 servers (I'm assuming due to the global stats and how that can alter a player's ability to level up properly). This being said, some servers do restrict weapons, but legal action could be taken (not a risk we're willing to run).
Also, there's a large majority of the player-base that is against such limitations on weapons.
It's no problem in most gamemodes though, albeit occasionally frustrating as you get repeatedly sniped...these snipers don't contribute much to make their team complete the objective.
I do appreciate your input and it's a valid argument, but I don't expect this will be happening on our servers.