this would obviously just favor bigger guns
which is fine for me, even more kills would go to my normal 37mm field gun instead of wirbles, fighters, etc.
wouldn't matter someone had hosed it down with 50's, or even 20mm's. 37mm takes off vital pieces no matter what, and thus with the OP's suggestion, would get the kill..
A single 20mm will probably not be a enough to kill a vital part, I'm not sure how many would, but 50s and their spray patterns are very good at getting a plane to soak up damage all over, as well as the previously damaged vital part. So under my wish-system, I'm not sure lower caliber weapons would be neutered.
I imagine now, a lot assists I get are from guys who sprayed up a large amount of damage with small caliber guns before one of my 20s or 30s finished them off. So under the new system, I would be getting those kills. However, there's many furballs where I just get a small snapshot at crossing opponenets with my 20s or 30s, so they would then be significantly easier to kill with smaller caliber guns from a friendly coming in after me. So I would in turn be giving out kills rather then having mine finished off for me in that scenario.
Look at your Kills v Assists as is, under my change, you would be gaining a few of those back as kills. But a few of your kills would then be traded out for assists.
I'm not sure a change would really alter your Kills v Assists ratio, but IMO would be slightly more accurate in recording what you have personally done as far as Kills v Assists