It's one of the things that I missed from Morrowind when I was playing Oblivion as well. I think having robes over armour and clothing beneath armour allows for much more customization, as well as a lot more enchantment. The large amount of extra enchantment could become a little overpowering, though.
This is where I disagree on it being overpowered. With my Morrowind character, by the time I could perform CE enchantments with an exquisite robe and good armor, I was already relatively strong. I still needed to do a lot of work to achieve it, and have a good bit of money or skill. Further, should it be as people always said with fast traveling in Oblivion, if you believe it's cheap, don't use it? There's a fine line between numbing the game and balancing it -- that's all I'm worried about.