Man in the Funny Hat
Hero
Pretty much just do what I've been doing for 40 years - making house rule changes for my own games, my most well-developed set being based primarily on 1E. The only difference is that I'd publish them, although knowing that they'd now be for wider public consumption I'd likely revise them again to accommodate a wider range of approaches to the game rather than quite so narrowly concentrate on just my personal preference.
If I were to use 3E/3.5 as a base it'd probably just look a lot like E6 (but I'm sure there would still be some significant additional changes). Maybe a set of "expansion" rules to 12th level but a lot of the material for that would then be heavily revised and I'm not sure what it would really look like.
I have no familiarity with 4E and I've barely played a minimum of 5E so they'd be of minimal influence.
