Polaris is the very example of poor character design and redundancy...

It was already canon before House of M.

There's no way she can "make up for it" in any way that would be acceptable to you without resurrecting Claremont and Jenkins' OCs that died on M-Day and Marvel re-powering millions of Literally Who? mutants and returning to a status quo they don't want to go back to.

After Morrison's run you have to deal with the fact that most mutants had mutations that provided no benefit or were detrimental to their lives. On top of that, after AvX you have to deal with the fact that most mutants aren't naturally occurring mutants, they were humans forcibly mutated by the Phoenix. If anything, there should be a massive movement within mutantkind going "Do it again, Wanda."

Funnily enough, so is her origin comic, and AoA and the Ultimate-verse.

I think that if they really want to have Wanda, Pietro, and Lorna as Magneto's kids they really need to do a full retcon instead of the "oh yeah, I'm your dad" stuff.