Having spent a lot of time wearing a cowl, it always did irk me that I couldn't wear spectacles or circlets with it to add a nice touch. Of course it makes sense that I can't wear a hat or a beret with a cowl, but spectacles or a circlet would fit just fine and look quite nice! Same thing with hats and glasses.

On the downside, they would probably need to adjust the stats of various items, since it seems in their grand scheme of stats 'n stuff they only allow for you to have one head/face item ( I mean, we can only have so many slots for jewelry, so they must have a reason right?). And then a lot of people would see the need to buy two items for their head instead of just one, which some people might find annoying (just playing devil's advocate here, lol).