[PvK]

Well, Mistform and Glamour are sort of weaker defenses than Etherealness that might be considered more appropriate. The problem is the SC potential because you have so many abilities on one chassis: Pretender, Immortal, Flying, Regeneration, Immunities, Life Drain Attack, ZERO encumbrance, all of which most units need magic items to get, plus she has full slots so she can add more on top. Most units need to use a cloak to get etherealness (or try to coordinate with an astral mage, which isn't actually that hard, though makes it a little trickier to coordinate other buff-assistants), but with built-in etherealness, you can add say, full black steel plate, too, which not only combines very well with etherealness, but also very well with zero encumbrance, and with Flying (which together negate two of the three disadvantages of full black steel plate armor). Also since she's an immortal pretender, she can have magic paths and not generally be afraid of losing magic when/if she gets defeated. Death and Blood give her stronger abilities for late-game such as Soul Vortex and Blood Vengeance.

I dunno. I sympathise more with the wimpier vampire forms, who used to have etherealness to give them good defenses, but now are not very formidable... except that they are immortals who fly, so they can add to a flying component (which benefits from critical mass, especially when it's cost-free and almost risk-free due to immortality).