The X-Men never invited Aurora to join them, even after her sanity was restored. Not only is she a speedster like Northstar, she's one of the very few X-Men characters who's actually a trained teacher. You'd think that'd come in handy.
They invited her, she said no.
Anyone else wonder how they managed to make Guardian's "power armor" (which allows him to fly, shoot laser blasts, do all sorts of things) as thin as any other spandex suit? Where does all that technology fit?
Under the "skin" of the armor. It's the Marvel Universe, if indestructible metal shields that can inexplicably be ricocheted off anything and be returned to its owner or particles that cause people to shrink or grow are possible, then spandex suits that can accomodate technologies are definitely possible. Plus, James Hudson did make a prototype version of his Guardian armor that was overly bulky, and one can assume he probably improved upon that design to make it more lightweight.
The suit's only slightly thinner that Iron Man's armour, which in the comics is only about as thick as a heavy sweater. The difference is that Iron Man's armour is designed to look like armour; Guardian's armour is sleeker, and covered with a layer of cloth.
And the cloth isn't even necessary to the armo(u)r in any way. In the "Unity" storyline, Mac uses his costume sans cloth in several instances.