If you manage to lob in a 75 inside the turret, yes, congrats , you have won the ww2 lottery, and probably died seconds after, because of the angle you need to get that one into the hatch opening.
You must also remember if shell explodes without delay on the exterior of a tank, it can not penetrate much armor at all, and normal angle of attack from a 200mph b25h can't be that high if you don't want to plant the bird at the distance you need to have a chance of hitting that tank at all.
There is more fragile stuff on the exterior of a tank than you would believe. Optics, engine components, track components, turret ventilation etc. As of the moment, I can't actually cite any WWII stuff, but I know of at least two M-1 Abrams knocked out by strange means during OIF. One was shrapnel that severed a fuel line that leaked onto the hot turbine. Crew couldn't figure out where the fire was coming from, even after using the extinguishers. Tank was abandoned and destroyed. The second was small arms fire that destroyed the fiberglass bore evacuator of the cannon. Couldn't fire the main cannon without massive amounts of toxic gasses flooding the crew compartment.
Now that I think harder about it, I can cite a few WWII examples. They are all Tigers ironically. In Africa, a 57mm bounced down into the drivers compartment afer hitting the turret, killing the driver, crew abandonded the tank. Then the famous example of Tiger 131 getting it's turret jammed from either 57mm or 75mm fire, crew abandonded the tank. A Sherman shooting a Tiger 1 with WP causing the crew to abandon the tank. And an M8 scout car shooting a Tiger 1 with 37mm from directly behind, destroying the Tiger.
