Any 20mm armed plane is far better for deacking -- fighters are faster more manuverable, can take out several ack guns in a single pass, but the reload on the 57mm was super long, like a minute almost, or something wierd. It was hand loaded. The ballistics sucked... So don't bet on using it for deacking. It was a small round, and an HE round (not AP) so it would be useless against Tigers/T34s, and there are far more capable planes to take out the lighter GVs.
It's a slow and cumbersome ride, the B25. So when fighters can do all the things you listed above, but only they can do them better, I don't think it has much use.
I say just give us the "normal" versions.
EDIT: the only problem is the drone system.. if you take a formation of solid-nosed b25s.... only you'll be able to strafe, and you might lose your wingmen while doing it. There needs to be a stronger formation link in b25s as opposed to other bombers.