It´s called ak47/M4
Increasing the rifle damage would only add another fastswitching great damage dealer apart from the Desert Eagle.
Well, those are only unlocked at late levels. By the time a new player unlocks them, they're already used to the sawn off/uzi/tec9 meta and will probably never try longer range
All the other weapons are only good short range, what's wrong with having another viable medium or long range weapon (beside the AK, M4 and sniper)? Like RedX said, the country rifle is a nice medium between AK/M4 and sniper, and is necassary to make long range gameplay viable.
Maybe fastswitching is a problem, but I doubt a small buff would make it more abused than it is right now (which is 0, never even seen somebody use it)