This idea would only be nice if people where able to put their own weaponset together and save it for the next time they want to buy their weapons.
So the only thing they have left to do next time is go to the bank, take their $$ and buy the pack!
I don't see any real advantages of weapon packs already been put together .
It takes less time to buy weapons, but i think people would be better of choosing their own amounts of bullets and their own kinds of weapons.
Or else you would indeed have to make alot of weapon packs for everyone!
So i would say, create a saveable weapon pack, or leave the current system as it is.