If you can not aim at a specific portion of a plane (especially a B17) then you're shot from to far away.
While I'm not good enough to aim at specific parts of fighters yet, I can and have aimed at specific parts of B17's and C47's.
Sims that artificially make the planes appear larger than they really are have always bothered me. Granted that aspect and detail would be easier to see in the real world than on a monitor, but there are to many difficulties in making planes larger. Such as making them easier to see w/o making them easier to hit from twice the excpected distance.
Anyway thats my .02
r2ch