Since Cata it has become a bit of a tradition that we get an older dungeon but in a new version. Some think it's Blizz milking the cow, others (like myself) get the nostalgia kick and enjoy seeing a dungeon that you used to level through, but now it offers max level content. Some of the revamps have been better than others, and sometimes the original is impossible to top (due to nostalgia alone), but we're talking theoretically here ofc.
So far we have gotten:
*Deadmines (Cata)
*Shadowfang Keep (Cata)
*Zul'Aman (Cata)
*Zul'Gurub (Cata)
*Scarlet Monastery (MoP)
*Scarlet Halls (MoP)
*Scholomance (MoP)
*Upper Blackrock Spire (WoD)
*Violet Hold (Legion)
I think it's interesting that out of all of these, all of them except for Violet Hold are located in Eastern Kingdoms. No love for Kalimdor? Just a coincidence. A revamped dungeon could be linked to the theme of the expansion (which we can only speculate what the next would be), but sometimes it can just be a revamp that stands on its own. Outside of the theme of the expansion, let's say a big threat rises in Razorfen Downs and we go there to take care of it.
I've always loved Maraudon but felt it lost some of its charm when they split it into 3 parts. Maybe tightening it up a bit, it could make for a great revamp. Always loved the atmosphere and feeling of the place. Same goes for Dire Maul. Awesome atmosphere and feeling, maybe time for some new love. Sunken Temple is another one that feels pretty straight forward and dull now. It has a neat look, but since they removed the two floors layout (which was confusing for pug groups), it just feels a bit too straight forward.
Anyhow, your ideas?