She's been the moral center of the Thunderbolts for a long time now, if you ask me. I haven't read every single issue that she's been in, but the ones I have read within the last, what...6 or 7 years, she's clearly been a character who has moved well beyond "Screaming Mimi."
I think she'd be an awesome Avenger, as well...I think her powers are really visual, she's versatile, she's tough, she's paid her dues. She's experienced, as well...I think it would be really good.
*Sniff, sniff* "Damn it, Diana...If I'd known they would trade us in for a JT Krul-written Captain Atom and "The Savage Hawkman," I'd have let Superboy-Prime destroy all reality.""Superman flies and is really strong...what the fuck else do you need to know?!"
-- Hitler, expressing his displeasure about DC rebooting and complaints about continuity