Orcs generally are also based on human faces, so it's not actually that bit that makes the difference.
Still, supermutant faces are pretty similar wherever you see them, because they're representative of what they are (as in, the physiognomy fits): small cranium, narrow eyes, big jowels. On the other hand, Adam's supermutants' faces are just...bigger than normal faces. But not disproportionate. Look at
this big face in the middle, how is that not just, I dunno, a barbarian in a comic book? He has big jowels, sure, but not so that he's clearly not human. Kinda different from mutants that have to use straps to hold their face up and have a chin you could put twice their cranium in.
The same way as you should view this whole "orc" thing as just looking for words to sum up all these changes, "hulk" is just a base of comparison. It doesn't actually mean the old supermutants were identical the Hulk, it means that you can see in some models of the Hulk (not all, he's gone through some changes) that he would have a muscle-growth disproportionate to skeletal growth as well as not equal in all places. This is also missing in Adam's supermutants, although they do look more hunching than the final product I saw in the demo.
For an odd basis of comparison, look at these guys
Adam's interpretation is closer to the two left guys, still clearly human. The original ones are closer (obviously, not identical, but closer) to the guy on the right (including, note, the head-to-body proportions).