I don't understand the question.
Do you mean take 2e and re-tool it by the fans and keep going?
As someone who's using 3e right now, GR already did that. It's cleaned up certain things (like the 3-18 attributes giving you +/- modifiers, instead of just using the modifiers), and so far seems pretty good. I'm not an expert on it, sure, but I don't think the changes are anywhere near as drastic as WoTC did to 4e D&D. Not by a long shot. The closest I've seen are the 8 attributes, but they only split Dexterity into Dex and Agility (so 6 is now 7) with the 8th attribute being BAB.
Or do you personally have an idea for M&M houserules that would make a good book on its own? I'll ask what the end product is. M&M is sooooo nuts & bolts that it's already pretty easy to do anything with it. Unless there's a specific setting you think needs backup with 2e houserules...
(WD: I get the feeling you have something in mind. I'm interested in watching the creative process, fyi. PM me if you don't do it (the idea) on this thread)
True20 mixed in: Okay, I see what you mean. Let me refresh on the T20 and think on it.
My issue with True 20 is that I can't find a group to play it with. It's simple, fun, etc., but my group was scared off by not doing the familiar. And so I troll these boards for inspiration...
Also that the first book wasn't enough. I recall wanting more blasty for mages, but that's my constant wish in new systems. Or was it some other need for the system... can't remember...