I'd be all for Gauntlet monsters and the like, just want to keep PSs in Fel ;P.
Since you have to be in a party to do T-Maps (with a group), I wonder if EA could make it so the stuff that spawns can attack specific members of the party. Like say an initial wave of 8 critters spawn against a party of 4 people. As it is now, all 8 aggro on the digger, who will be invised twice (or thrice) by the group. Then their gdrags etc do the work. What if the guardians aggro'd anyone in party initially, instead of the digger? Not sure the change would add that much more difficulty, but I know the new client allows targeting by party member, so I wonder if EA could implement that for monster AI as well.
Tormented Minotaurs, to me, seem like the nastiest thing in game that isn't a boss. Yamandons can be pretty nasty too. The Undead Gargs outside tomb are nasty, but defeated by a group fairly easy. Abcess has nasty potential at first, but degrades -- and I don't like to break locality, but EA did it when they put Coil in the Stygian Abyss Underworld, so I figure he or she is fair game.
Other hindrances for a LvL 7 could include the chest relocking and/or trapping without warning ... or more predictable, perhaps after each spawn pops up. Rate increase would be interesting too, or even an increase of the gibberling(sp) or whatever that thing is called that will steal items ;P ... imagine 20 of them spawning at once, haha. Either way, I def agree a LvL 7 should be an epic fight -- which from what I gather, it is not, yet.