With artilery is should be splash damage, it cant kill a player or vehicle with one hit but it could destroy a base turret with one hit. And ofcourse slow mobility.
Bomber should be powerful, as powerful as artilery, but as in the air, its up to the gunners to keep the bomber safe. OF course there will always be some kind of air force the enemy should have. But then also if the enmy should not pervale, the bombr doesn't have infant bombs, or 100 bombs (unless they ae really small). At the most 30, and ya mus reload at home if ya ever want to drop bombs again.....or you could let the bomber fall and go build a new one....