The way I understand it, Quranism can really only exist in a context where an Islamic community rejects sharia as source of lay law, since the Hadiths are, in effect, the actual laws to the Quran's "constitution", and without it you are left entirely with the Quran's vauguer precepts, assuming no binding imam authority is recognised.
This has the obvious problem that, in effect, in order for Quranism to be mainstream, the Muslim faith needs to be dominant only in select areas... which goes counter to your "majority in certain regions", because then the majority of muslims would be actually be a minority in the territory they inhabit.
ETA: also, realistically, a a "Muslim Reformation" would mean reshuffling the hadiths, not abolish them.