Remathilis
Legend
Im actually predicting a 5e (Quite a few years away) that will have 3 versions. They'll all be derived from 4e, but will push the ruleset in different ways.
"Main" will be a logical refinement of 4e, like 2e from 1e or so.
"Advanced" will be a more simulation derived rules set.
"Basic" will be a more rules light version that ditches the grid in a balanced way. this will be a subset of the common rules of the other variants.
The key trick here would be that all three versions were cleanly translateable in some way. A Basic Monster's stats would work in Main or Advanced. It would just be a simpler monster with less powers and detail.
Of course I'd also have a highly genericized version also compatible called d20 Fantasy...
TSR did that for years; look where it got them.
Part of the oddity of D&D is that it was never a homogeneous game except for a small amount of years after its initial release. From 1977 to 2000, there was two D&Ds, Basic (growing from the OD&D and Holmes/Metzner/Moldvay/Cook) and Advanced (growing from Gygax's AD&D) which splintered the fanbase. Only since 2000 have we been able to talk of D&D as a single game with a "default" set of assumptions. (Whether that is good or bad is beyond the scope of this discussion).
While the idea of creating varying complexities of D&D might appeal to some players who want more/less detail than the current editions provide, I think it would go a long way to splintering the fanbase again. A much better alternative would be a game that allowed a slide-scale of complexity (either modular enough that you could remove rules without breaking the game or starts simple with the ability add complexity via supplements).
Heaven knows though, that doesn't appear to be the direction the game will probably take.