I will try it tonight... I thought it was hard to solo.
I've run Challlenge of Elders solo a number of times, both for score and for the drops. The modifiers this week aren't conducive to running the Challenge solo this week. I mean,
you can, but it would be a struggle if you're not really familiar with it.
Edit: I actually thought this week was the other Cabal guy, but it's Noru'usk. He's a bit easier because he doesn't roll with Flayers, but the adds in that room can get overwhelming. Each of the add waves are DPS based, so as you do damage to the boss more and more dudes come out. It's not really an issue with the other two bosses, but the Cabal arena can get rough.
If you're gonna solo it, I'd suggest waiting for the Primary or Special modifiers.