That is an excellent retcon and it kind of turns classic Maxima into that parent who is living vicariously through their child, which I could totally see her becoming had she lived long enough.
Makes for an interesting parallel to Clark, too, since she'd be the controlling parent and Clark has been a bit too hands-off since Bendis took over. I know this is a PG thread, but that does sound interesting.
Have PG and Maxima ever interacted? I imagine Karen would not get along with classic Maxima.