I started to like to shoot the weapon (Minigun always) out of opponents hand, so he start automatically Melee or HtH. Its not like F2 wenn cripple an arm you can't fire Two Handed weapons anymore, so shoot it out of his hands
With the supermutants you want to take out the missile launcher or minigun first. Those weapons are typically already damaged so can be destroyed easily. The supermutants take a few shots to take out.
I only shoot at the weapons if they are big guns like minigun or rocket launcher. This is pretty usefull because I hate it to get hit with that stuff.