Frankly, the massed heavy weapons thing is probably kind of a stopgap, and it's got drawbacks- a lot of collateral damage that's only remotely acceptable because in a situation like this there's extensive efforts to pre-clear firing lanes and ensure that the buildings actually in danger of getting chewed up are evacuated.
Having actually magic-proficient soldiers and some kind of way to systematize their equipment would probably be a good thing, and there are likely to be voices within MCAT that are tempted to just say 'fuckit' and go with a melee-oriented all-yokai force if they can figure out a way because that tends to cause less collateral damage.
But human beings can't melee with a lot of the stuff MCAT expects to fight... well, not without something that confers the physical strength and durability of at least a low-end magical girl transformation, or highly magical melee weapons and armor of a type Onogoro has a lot of and MCAT has very few of.