I don't think there's a mismatch, maybe because I don't consider his face "boyish" like other do. Yeah, he doesn't show his age but it doesn't mean he looks like a boy. Especially in that promo, in all those close-ups and with that look. IMO his lineaments are everything but boyish.
And good to see that MC had more to do and say in those 3 minutes promo than in the last season of TGW (and in the previous ones). I'm going to watch it even if only for that reason.