David Bowers touched on this just the other day, and the WoW community has mostly seen this change as a negative thing. Example: The original thread from the official forums.
My favorite little change out of the various, random character model changes in patch 2.4 is actually the change to the human female eyes. Sure, it looks silly in some cases, but for my own characters it was an improvement. I could never find the perfect eye choice for them before, because they all looked either empty and sunken, or incredibly angry. I'm not sure exactly how to describe how the eyes look now, but there's some sparkle that wasn't there before. I like that! Yeah, there's some that look horrible, which is lame for the players with those particular eyes. Overall, though? I like it. Even if the iris seems a little over sized, they have character.
The outcry over this very minor detail drives home a point that Blizzard has made before, too. It's a very unfortunate one. The character models most likely will not receive any substantial overhaul in the future because there will be a lot of people very angry about it. I didn't really want to buy into that, because I really want updated character models, but it seems much less likely after this. Such a big deal over eyes is not a good sign when it comes to model upgrades.