Run Magister's Terrace. (Normal mode, not heroic... I'm not insane. Yet.)
At this point, I've managed to solo (or two-man) quite a few instances with Aetherna. I figured Magister's Terrace would be another "trash is a pain, but doable, bosses are right out" sort of instance, like some of the other higher-end BC content.
Yowza. I was right on the trash mobs. Pulling a pack of 5-6 required a good use of polymorph, slow, frost nova and mirror image when things got hairy. Required some planning, but aside from that, it was just a matter of CC + making head 'asplode.
The bosses, on the other hand? Wow. Selin Fireheart went down on the first try. Clearing the room for an attempt at Vexallus was interesting, but once I managed that, I got him down to sub-5% on two attempts before doing a bit of reading and realizing that I need to hold off on my cooldowns until he hits his final phase. With a little different strategy, and perhaps a Flask of the Frost Wyrm, I think I can manage to take him out before he completely fries me.
The adds on Priestess Delrissa may be a bit hairy, but at this point, I'm fairly confident that I will eventually be able to make it all the way to Kael'thas. I don't know if I'll be able to take him out without assistance, but I'm certainly going to try.