Yes, that throne room has so much significance in the Warcraft/WoW universe it is amazing.
Yeah, it's a real shame he was so underused as a Hero. Liches are fantastic, and I loved his abilities. And that voice acting (except in WotLK, stupid how they got some random guy to do it there). Michael McConnohie delivered Kel'Thuzad's lines perfectly.
Yeah, I fully agree about Kael'thas and Illidan. They were fantastic characters but Blizz needed raid bosses, bleh. The BC races didn't fare much better imo, the fact they refuse to do anything with Lor'themar or the Draenei as a whole doesn't help matters. Barely feels like the Blood Elves have a leader or the Draenei are even still part of the Alliance. Heck, Tyrande doesn't even send an invite to Velen for that very reason. Hello Blizzard, if you're going to lampshade it why don't you actually fix the problem? :/
Arthas and Kel'Thuzad, first and second favourite villains in the Warcraft franchise, and my favourite Hero characters in WC3 alongside Maiev. I loved Arthas' story, and that scene when he returns to murder Terenas, just wow. Just the feeling that there is no turning back for him now... epic.
Night Elves are my favourite race, even moreso than the High/Blood Elves. I found the Night Elf Campaign in Frozen Throne even better than the Reign Of Chaos one, thanks to Maiev, Illidan, Tyrande and Kael'thas and exploring the Broken Isles.