This is a hard question. I do enjoy the idea of Lorna, Pietro, and Wanda, being siblings, but I just don't think it will ever be executed the way fans want it to be. With Polaris being an X-Man first, and Scarlet Witch and Quicksilver being Avengers first, the House of M doesn't really work as well as does in other mediums (comics vs film, animation, video games, and AUs). In the comics, when they were family, I feel that Lorna often get's forgotten when Wanda and Pietro are in the picture.
I do enjoy the prospect of Polaris having connections outside of the X-Men, but even then most writers don't really do enough with it. Pietro was the only real exception to that, and even with it being well developed, look how long its been since either has mentioned the other. I guess this is just a really long-winded way of saying I'm not really clamoring to see them added back to the Magnus family, but if it happens, it happens.