Thats the point. Because you can't buy vet in CoH2 (Not talking about Elite Commander now) this shouldnt be a problem. And if the opponents can punish you by killing a vetted squad (wich is also harder to take down) he should get rewarded.
Not saying you should lose the game by losing one squad. But you should feel it and not being able to replace it in a couple of minuts.
I dunno, before squads constantly touched dicks (so it's way easier to lose them now), regaining the vet was quite possible, but still took valuable time - a rifle infantry squad felt like it would likely at least take say 10 minutes to get vet 3. I thought it was at a pretty good level then.
But now when advanced AI vehicles come out, squad-wipes probably follow one after the other when the replacements arrive.