Definitely agree. I love the Thalmor outfit on my Altmer mage but not on my soon to be created second mage.
Also unenchanted Thalmor robes would be nice as the enchantment on them is only nice at lower levels but the same goes for any unique faction clothing/armor really; would love to be able to get the unenchanted versions.

Radiant Raiment has some fun stuff but it is all kind of the same. I would love more garb to enchant. Sometimes you see cool NPC garb that just isn't available. Like Syl's dress from Shivering Isles, would have loved that for my female char.

Just as you feel your char is unique he or she should have the option to look unique.

I think Skyrim has a pretty decent array of clothing, comparatively. Dyes are a good idea though. Might be hard to implement, not sure.

If anything bothers me it's how rare the likes of unenchanted hooded robes are.