I'm in great favour of a transmog system. While I still have to find the "phenomenal looking" (vanilla) armor (except one robe it's mostly ... meh), a transmog ability allows for individualisation, always a nice feature. For example I don't want to wear gloves with enclosed fingers on my lighter armored or casting chars. I want sandals on the feet of some lightly clothed chars instead of terribly looking boots which only fit to medium or heavy armor visually while not having the armor group label (Nere's boots for example).
The transmog mod I'm using works fine but having it in the vanilla game would be better.
