Thanks for you suggestion Wilson. We've been hearing this suggestion for a while now from many players. We've discuss it, but we decided not to add this because players would make overpowered packs like spaz, m60, molotov, etc..
We made each pack carefully so that each one has its own advantages and disadvantages. It's what makes the gameplay balanced, and since this server is starting to be used for clanwars, balance is our top priority. We don't want to upset that balance.