Hmm. And here I am wondering how Shooting Star will stack up with a defense shift (which can lead to glass ninja problems, as Elric mentions), lowish base damage and no Power Attack (she can't hurt Spirit and similarly impervious characters even when using Extra Effort for +2 damage).
I'll readily admit that she could be incredibly dangerous in good conditions. The ability to do high speed flying move bys (forcing most opponents to use Readied actions to attack), then launch indirect attacks from cover (negating most readies) and finally, have triggered powers waiting when they attempt to storm her supposed position (then stir and repeat) might be able to confound some teams if things go according to her plan. All she has to forfeit the chance to protect innocents, injured allies, etc - her best strategy for winning is generally the worst for superheroing
Generally, a character's combat caps are what determine their effective PL. With zero dodging ability, pretty much anything can hit Spirit - she operately at an effectively weaker overall defense. Of course, with pretty good saves and 14 Impervious Toughness, getting hit is not generally that bad, normally. But her defense is so low that even people throwing everything into Power Attack will still hit, and that greatly reduces the effectiveness of her impervious toughness.
However, it's not going to be the end of the world if you have 10 defense. It might take new opponents a bit to figure out exactly how big a target she is and thus what their Power Attacks should be (and they might not have it, which reduces their ability to take advantage). You can change up your defenses with Concealment or Insubstancial as a counter to full Power Attacks. You could use Morph to pretent to have another character's defenses. If she takes a bad hit, Spirit can suck on a power line to restore herself. I get the impression she hasn't been Spirit long - that she just developed the powers and fought the assassin (not sure if that's what you meant). It might come as a total surprise to Jessica that she actually can be hurt, that dodging might be helpful.
Given her defensive options, high impervious, and decent saves, Spirit can probably avoid incapacitation about as well as other characters despite a low defense score. Just remember to use those defensive options to throw off your attackers - those points in APs could easily be Luck or Dodge Focus if you don't use them regularly (in that respect, Shooting Star's corrosion cone is probably a waste, but I think it helps establish the dangerousness of her powers).
