It's not a new idea; people have been suggesting it for months.
My take?
1)
WotC can terminate your license for any reason; while I imagine they'll be fairly lenient, and many companies could fly under the radar, one should remember that using clever tricks to try and weasel around things can always result in
WotC saying "we don't like the way you're playing, so we're taking our ball and going home".
2) The only reason to do this is if you want a product line with
OGL and 4E versions; you can still happily produce
OGL and
4E products as long as they're different product lines. Having different versions of the same product line published and sold by two different companies would be confusing to the customer and possibly counter-productive, being the antithesis of effective branding.