02/24/2012 07:02 PMPosted by Vyrin*Sylvanas says she's going to do bad things to Koltira, and Thassarian says he's going to go after him. Both situations are ones that are likely to take some time; the former as Sylvanas slowly turns him to her side, the latter as Thassarian investigates both where Koltira went and how to get into the Undercity without immediately getting slaughtered by Kor'kron.
Thassarian then subsequently appears in the Firelands, apparently having forgotten all about rescuing Koltira and restoring Lordaeron.
I WOULD kind of sort of be willing to cut them some slack on it, just because it was obvious the cameos on that quest were more "Haha hey remember this character" than anything that made sense from a canon perspective, but it really doesn't speak well to their chances of ever properly following up on it. I mean, Thassarian literally abandoned his post, his commission, and the battle to save Koltira. That generally doesn't imply "Oh, I'll wait around a few years, let Koltira get brainwashed a little, maybe take a detour to do a few other things, then. Eh. Eventually I'll rescue him." This the guy who had the willpower to essentially resist the pull of the Lich King in order to hold up the battle and send new DKs to save Koltira.