When the Icy Raiments were moved from Ghosts of Perdition to the Garamol encounter in the Subterrane, along with having his chest drop the weapons originating in PnP (Sun Blade, Mace of Smiting, etc); it reignited a lot of interest in the Subterrane in general. There are now semi-regular "Icy Runs" groups on most servers, and they're a good way to get a bit of slayer experience, Planar Shards, loot, and fun outside of normal questing and raiding.
The Subterrane, however, is a much larger and far more interesting area than just the run to the three portals to Garamol and the run to the VoD and Hound raids. One of the most fun and enjoyable encounters is the Eye Tyrant's Council room in Subterrane East.
You fight your way almost to the entrance to the Hound raid (use the shrine where the Render of Madness can spawn at the "Madness Aperture"), then head into the other portal ("To the Deep Tunnels"), take a little swim through a pool of acid, and emerge into a room full of treasure and two chests, guarded by a group of Ancient Beholders. Another group posted screenshots of it.
For being a time consuming but fun run down to, and a definitely challenging fight even with good Archmage CC (SLA's can be used while in an antimagic aura) and well equipped melee's, it's depressing to have nothing better than the normal explorer area loot (lower level than it would be if it were a 19-20 quest).
I've taken about 10-15 people down to see the area now, and all thought it was a "cool area" but needed something more to draw some interest.
It would be nice to have a chance for something useful to drop in those chests. Beholder protection items, or Abberation bane weapons (also good for eOOB), or something useful against a possible future Daelkyr raid boss.