Hit 250 skill this weekend, for some reason I can't find my Greater Nether Essence (buried in mail? lost forever? don't know!) so I did it with lots of Vision Dust insted of GtNE and Dream Dust. After 245 it is very expensive in terms of Vision Dust per skill point.
By using the backdoor into Uldaman you can get to the trainer very quickly, so overall the drawbacks of her being in the instance isn't huge if you can call on friends to get you past the mobs.