O don't think it's about being lazy, it's about not putting the resources into it. Totally legitimate imo. Just mean they can put more time and resources into something else
The technical possibility is already there, so the only thing would be balancing encounters. Which is possible, but as you say: at what cost and what benefit? So I think we have strong points speaking for 4 PCs and not too many points speaking against it. The whole thing "but I NEED X or Y or Z in ANY party" is plainly wrong and the only factor that would drive such an argument are the balance changes away from 5e.
