I would say leave stuka as it is, but buff other stuff, especially buildable Howtizers, and especially self-propeled ones like Priest and Sexton, cause now i fear (and use) Pack Howie more than real howies with greater effect, and it aint normal. Artilery is joke in this game, itš either to week or comes too late, actually i loved British op abilieties when they were op, at start, they made me fear them, made me take actions,l now when i see 350 muni bomber run, i just laugh my arse off and move everything away with no damage (just repair some trucks after).
As i see this ability can be problem in games with more than 3v3, but from my experience i go to em when i want to see a real clusterfuck, some war action ,and i basicly get it so whats to whine about. AND do u 3v3 (4v4) players want to say me that u go to play these game modes for strategy, or u go to play them just for fun (action/death/clusterfuck)? I bet its 2nd answer, then get it that fun is relative - its botth fun to blow blob up with stuka, and with calliOPe alike.
In competitive levels, where u need to think more, than just spam shit - i mean 1v1 or, to less extent 2v2, stuka bomb isnt much problem.
The AOE is so large that it is hard to get a pack howie out of the blast zone, even if you respond right away. Same thing for 57mm at gun, and having a Vet2 or Vet3 at gun decrewed when you've almost backed it out of the blast zone is really annoying.
I don't often see the stuka in 2v2's but if one hits it often swings the game. The AOE means that you can't all of your major, ambulance, and units out of the AOE.
TBH, one of the annoying thing about off-map air in this game is how completely antihistorical it is. The tiny remnants of the Luftwaffe in 1945 mostly tried to defend Germany for aerial attack, not close air support. There really shouldn't be a Stuka loiter, dive bomb, etc. On the other hand, US should have much better off-map air.