I'm on board with the champions, so far. But I've also only run the 10-13 range quests since the update, so mileage varying etc.
Two things to note:
1) I've run into a couple that would've stopped a solo run like a brickwall, namely HP or defense buffed self-healing champions. Scorrow priests, for example: I couldn't out-dps their healing, running a super-geared barb with 20 past lives. Not a low-dps toon. I'm not saying it should be nerfed to oblivion by any means, but that seemed a little.. excessive.
2) Tomb of the Tormented. Champion carrion eaters in the maze. Come on. QA.