Like Karnak said, be it a more crappy plane than the Hurri2D(which, is a fighter, and the Stuka is technically a bomber), or possess less ammo, doesn't matter at all.
Again, the only thing that matters is how well it can do its intended job. If it can do its job so easily as to make a certain portion of the gameplay nigh useless, then it needs to be perked.
Imagine a slow, lumbering 4-engined bomber that carries a nuclear warhead is to be introduced in the game. When the bomb is dropped, it will obliterate everything, be it ground object or a plane in the air, within a 10 mile radius. So, because the bomber is so slow and weak of defense, should it be non-perked? Is it the bomb alone not worth perking?
I don't care squat about how easy it is to kill with fighters. I think from the GV perspective, and that perspective tells me that if there are free Ju87Gs flying around bases, I'm never, ever gonna up a tank to go rush a town or field ever again. I'm gonna up an Ostie, and go hit towns with Osties. All my friends will also be upping Osties, because, there is no reason to ever up a tank at all ----- just like the old, AH1 days. Say adios to the ground war as we know it, and welcome back the old, bland, stale, Ostie swarms.