Good points, Sax, spaz.
Still, it seems the lesser-capable bombers are worth more than they ought (this just an opinion, only based on my thoughts).
If this were a B-26, B24, B17, capable of defending itself, more likely to kill the attacker than to be killed, I can mentally justify a higher points total for killing it. I think for the lesser bombers, perhaps "normal" scoring should be used. That is, it's worth no more than the most valuable fighter on the same team.
If you've got Ki61s worth 5 points, Ki84s worth 8 points, and bombers worth 20, then the bombers would be dropped down to 8 points.
I haven't tested it, I don't know all the stuff the CMs know, so I honestly can't say I'm right, but that's what I'd like to suggest.