Illidan was certainly the most difficult fight I've tanked - requiring an insane amount of concentration, flawless shield blocking, positioning, and cooldown managment. All of the traps placed in p5 were terrible, so I ate all the enrages (which really weren't that bad). I'm glad that I did it pre 3.0, when Sheer is supossedly getting removed (I'd liken it to Archimonde having Fear removed - a fairly key part of the fight).
After the dust had setteled, and the phat (non-tank) loots distributed, Ruffianx (our GM) did some promoting. He had announced a week prior that he would be leaving WoW to get a better grip on his real life, but wanted to finish Illidan with us. I was made the new Guild Master of LOKI, a change that seems to have been well recieved by everyone. Jerey, our Paladin tank, was promoted to Tanking Officer.
I believe I'll be able to lead LOKI to future glory in Wrath and Beyond (with the invaluable assistance of our officer base), but it will certainly be a different place without Ruffianx.