In my humble opinion, Blizzard has no need to try and make great looking gear anymore now that everyone will be rolling around in Vanilla gear. No longer will we see new tiers that are Transmogrification worthy like the majority of the low level tier was. If anyone would bring up this problem, I can picture them passing it off with a simple "try Transmogrifying your gear to make it look better."
Maybe I'm just over reacting, maybe I'm not. What does everyone else think?
P.S. People have brought up the idea that there should be an interface button to disable viewing of Transmogrified items, this seems like it would be a pain to make but I think it's the best solution I've heard yet. Then at least it would be a win-win, if you wanted to RP some with some friends in old gear you could, but if you wanted to raid without seeing people looking like all different colors of power rangers, you could too.