...and for Cat dungeons also for that matter, but it might be too soon to bring those back since it was only last expansion.
But basically, I really like the concept of Challenge Mode Dungeons, and personally think that TBC and WoTLK dungeons are ripe to get the challenge mode treatment. They were all (or most at least) designed with a post-vanilla design philosophy in that they we're all more or less linear and streamlined, and built with the concept of being completed in 30 minutes or less.
I'd like to see in a future patch 3-4 dungeons from both TBC and WoTLK updated and tuned for challenge modes. The idea is to pick them based on popularity, interesting fight mechanics, art design, lore, and other factors that made them fan favorites. Of course, I'd like to see this done more than once, and eventually see them all implemented. But here's the ones I'd pick for the first batch...
Burning Crusade
- Hellfire Ramparts
- Shadow Labyrinth (With some trash thinned out)
- Steamvault
- Mechanar
Would have picked Shattered Halls and Sethekk Halls over Steamvault and Mechanar, but felt it was more important to get variety and not pick two from the same instance hub.
Wrath of the Lich King
- Utgarde Keep
- Halls of Lightning
- Drak'Tharon Keep
- The Nexus
I'll pick four Cataclysm dungeons also, even though I think they are a lessor priority at first.
- Halls of Origination
- Grim Batol
- Stonecore
- Vortex Pinnacle
Now you're probably wondering....what about Vanilla dungeons? I personally feel that Vanilla dungeons are best suited for "Remakes"...in the vein of Scarlet Monastery and Scholomance. Put a greater effort into these to redesign them with updated bosses, story, and layout and include 2-3 of them each expansion...which in turn would give us their challenge modes anyway.
The TBC and WoTLK dungeons dont need to be redesigned, just scaled up and tuned for challenge modes. Which would make it easier for Blizzard to do a batch of these once or twice an expansion in a patch update.