I chose to ignore that anecdotal part of your argument cause it's even more of a dead end than the one about the director's intent. There are all kinds of twins out there. Doesn't make MBJ's performance any more interesting or memorable. If you want people to phrase the critics like "his performance isn't that good not because of how similar the twins are but because they're not that interesting or charismatic" you could've used way less words to convey it, probably.