The disappointing thing about Marvel, and especially Bunn's writing of Polaris on Blue, is that Lorna getting real effort into her development shouldn't require Magneto going away. They should both be able to have a strong presence on X-books and both have strong moments that don't undermine the other, especially when they're on the same page. In the hands of a good writer, there's no reason the two can't be around simultaneously.
Honestly, a huge chunk of the reason I want Lorna off Blue right now if things don't change for the better is that I don't want their potential together ruined. I don't want to see "if Magneto is around then Polaris can't be around" and vice versa. I don't want to see the writing I've seen on Blue result in their relationship becoming so toxic that they need to remain separated for years to a decade to fix the damage done to it. I'd like Bunn to be better than this. But if he can't be, if his fandom for Magneto and his year-long work on the Magneto solo have creatively blinded him, then it's better for him to not use her. Let someone else write her, and let that someone else use Magneto too. Do what he can't.
I don't want Magneto to be an obstacle to Lorna's potential, or vice versa. Recent writing is turning him into one, and I don't like it one bit.