I agree that I think having an MC who stutters in a novel about other stuff is the best way to go and I don't think it's minimizing. Especially if they're the hero, or they're important and cool, kind of a badass basically. I've always wanted to read a noir-detective type thing where the grizzled detective gets loads of great one-liners and he stutters through most of them! But I'd take anything! One thing I'm kind of iffy on is when the end of their arc is them delivering an important speech totally fluently. I feel like that shouldn't be the end goal or the peak of their life in the novel. If they have to do a rousing speech or something I'd like to see them stuttering during that, but still killing it.