Hmm interesting thought. The insane is allredy hard to beat. Makeing it harder, by removing the repair kits you get from boxes, would only make players spend tokens to revive.
I see no end benefit from it, except maybe if the rewards were incredibly high.
Further more, adding even a slightly higher dificulty to the mechs in the last zone, for example Big Boy, like even 10 more cooling, or 100 more hp, or 5- more dmg to weapons, would make him unbeatable.
On insane you requier fused weapons +10 at least, to actualy stand a chance.