Like Iceman said, firerate doesnt make the gun any more powerful. AA12 is fast. Dual Auto Pistols are fast. But you do realize that a rapid stream of bullets can be easily avoided, right? Plus, your idea of balancing firerate on most guns is to add more freeze, which makes trying to both dodge AND hit your opponent a pain, assuming you actually CAN in a specific sitiuation.

The only weapon I know of where the firerate matters is the dual five-sevens, but they have a good spread and freeze on them to actually compliment that.