(Reasonably sure this doesn't already exist in-game?)
I'd say that an easy way to buff/nerf some weapons is to have different base charge times. I'd assume most bombs would have shorter base charge times, and heavier weapons would have slower ones (e.g. troika lines, autogun lines etc). Faster weapons like the cutter lines or antigua lines could have shorter ones as well.
You might also be able to use this to nerf Brandishes since their charge attack is really good, so making it charge slower can help at least a little bit with that.
