If they manuver, they have to take the time to recalibrate properly instead of holding down a button for two seconds. If they care more about getting their ordanance onto their target, they will defend till they hit the drop point, hit their targets, and then either bail out of their shot up aircraft, or hop back into the guns. If they care more about landing, they will fight off their attackers and make another pass, or use their inaccurate bombsight to get a rough idea of when to drop, and carpet bomb their target.
I don't bomb a whole lot since level bombing will never be a good way to play clean up at town, or to hit ack, but when I do it is much less fun than when I bomb in FSO. The funnest bomber run I've ever had was in FSO when my Ju-88 was attacked by a group of spitifires, and I lost 2 drones. I didn't even destroy my target, just get a few 100lb bombs on it because I had my delay set to 0.15, I lost my drones, dove to the deck, and fought some spits untill a group of 109's bought me time to slip away NOE. Best bomber sortie I've had, hands down.