I would contest that the vision of a creature is just as much a gross, physical feature as having claws, wings or legs. It's certainly far, far more of a gross physical feature than having the skill to rake someone with your rear claws once you've grappled them, or knowing just how to wrap your elongated body around someone in order to strangle them. Or for that matter the knowledge of how to swim or breathe once you're a fish or burrow if you're a wolverine. Would you still grant blindsight and tremorsense? Would you grant any of the capabilities of a beholder? Because it's flight ability is apparently (ex) despite being due to the beholders body being 'naturally buoyant'. And it's all-around vision, also an (ex) ability is certainly due to a gross, physical feature, that of having a lot of eyes pointing in all directions.
And hong - your reasoning is quite facetious. Perhaps you would ban people from staying still? After all, the only creature with that (ex) ability is a gargoyle, and gargoyles don't exist in real life! And hey! Noone's allowed to throw rocks, because the only creatures with rock throwing (ex) are giants, and... everybody together!... GIANTS DON'T EXIST IN REAL LIFE!
All this discussion is doing is proving that polymorph is still a stupid spell as written. Either it needs to have a significant rewrite, specifying precisely what it is that it grants or doesn't grant, or the monster manual needs to be rewritten with the additional ability type of (na) for 'natural'.