Neat concept, not sure how it would work out in play however, Bombers are a cool idea but, imo, removing the current unit's ability to airstrike ground units would be a step to far and drastically minimize the usage of the units. Perhaps removing Infra damage, having Bombers be Infra damaging with similiar rates of casualties when hitting ground/see? Alongside, would there be a new improvement for the bombers or would it split the hanger space? So you can split your planes and bombers by percent (so like 70% planes, 30% bombers) or would it be a 50/50 split?
Cool concept though