The issue with Wanda is almost the same one Jean initially had when the Dark Phoenix Saga happened - both had committed such terrible acts they couldn’t be seen just be heroes again. Jean was killed off, and Wanda disappeared for 10 years.
I think Bendis might have had an idea with what to do with her, but the Young Avengers writer wanted to resolve Billy and Tommy’s storyline so they did Children’s Crusade which resolved pretty much nothing, and retconned the situation poorly.
It’s a complete mess. And it’s not even just M-Day - for someone who caused the worst day in Avengers history, there wasn’t a lot to address that either.