I'm not really sure what the whining is about with formations. Sure, if you saddle up on a formation's 6 o'clock at 400-600 yards out, you're going to get cut to pieces. That's as it should be. There's a really good way to shoot down whole formations of bombers, and that's not to saddle up on their 6. Try actually using attack angles that are hard to defend against. I personally love a full formation of bombers rather than a single one. It means I can get three kills instead of one.
As for the OP, I'm all for it. The scoring system exists, for better or for worse. I'd say counting aerial victories against marauding fighters makes at least as much sense as counting a "bombing" percentage in GVs. Actually, it makes way, way more sense. How "score hoar" is it when guys (I've done this too) take an Sdkfz 251 with rockets into a town and blow up buildings, just to boost their score. And yet a guy's bombing score isn't affected by being a really great defensive gunner and killing lots of fighters that attack his buffs?
I really don't see how the OP isn't perfectly sensible in the context of a scoring system that's not going away. If "bombing %" makes any kind of sense at all for the GVs, then certainly defensive gunnery kills ought to count for bomber rank.