Hamilton is about 90% impossible to stunt cast, and it's demanding enough that the "name" people who could drive tickets to the show are such gets of such talent that you wouldn't call them stunt casting per se. If Usher stepped into Burr, it's technically stunt casting, but it's USHER as BURR. Nobody is gonna call him unqualified or a hack.
The only stung casting that would actually ruffle feathers, while probably also being great, is if they somehow got Eminem for Hamilton. Because, yes, on the one hand, it's a middle-aged white guy in a role traditionally played by a young actor of color, but on the other, Em is the only white guy to ever be considered one of the GOATs of hip-hop, and is the personal inspiration for much of Hamilton the character's flow and diction. It would be controversial, but probably not "Great Comet" levels. It'll also never happen because Eminem doesn't want or need that role and hasn't acted in ten years, so there's that.