Lusche,
You've been playing a long time, and I've grown to respect your opinions on this board.
I can only speak for myself here. When I see bombers, it really doesn't matter if they're incoming or outgoing, I still try to kill them if I have the speed and alt to attack them properly.
Again, speaking for myself, I wouldn't NOT attack bombers inbound just because if I killed them outbound their damage wouldn't count. I'd try to kill them both ways. I don't think such a coad would change the tactics of fighters attacking buffs, but then again, folks have an amazing capacity for finding the gamey exploits in this game, so I suppose such an attitude change is possible.
At any rate, I can see your point that this would penalize buff pilots doing their thing 'for real' but only if they came in in a manner that allowed them to get killed within a few minutes of bombing. I've only flown a handful of buff missions, but I've found that getting over 15k thins out the opposition significantly. When I fly buffs, I figure I'm commiting at least 45 minutes or more to the mission to allow for climbout and transit to target. I assume I'm going to have to spend 20 minutes getting to alt. So, the idea of a mass of fighters attempting to kill me RTB doesn't really bother ME- I plan my route to drop on my egress heading, and a set of buffs at full speed at alt is NOT easy to catch and attack properly. So, in my opinion, all you've done by coading a time delay on permanent damage is force 'real' buff pilots to fly at least at some sort of survivable alt and use a smidge of planning in their attack.
I agree that it's trading one sort of gameyness for another so I suppose the question is which sort of gameyness you prefer? For me, the bomb and bail guys and the suicide porkers are the most distracting things in this game.