I don't think Naima's moves are all that great compared to many successful performers, but IMO they sure are better and more interesting than her competitors'. (There are people who love the way that Paul moves on stage, but I don't. Some people can't stand the way he sings (though I think some people may be hearing with their eyes, but I like his tone.) I wouldn't go so far as to say that Naima's vocals were better than 95% of the Grammy performers', but it was as good as some there. I'm not sure that's a good jutsification for keeping her around until the end, though, if there are people who clearly are outsinging her. If the singing isn't the major factor in this show, why bother pretending that this is a singing contest? I don't see the point in crowning someone just to autotune the heck out of them in the studio. Naima adds interest to the show, so I'm glad to keep her around until some of the boring mediocre singers are sent home.
I'm curious to know how much the producers brought in to work with the contestants are determining the arrangements. I think some contestants will benefit from the producers and some might be getting stuck with arrangements that the judges and a lot of viewers don't like. Naima's arrangement worked for her. Thia's and Stefano's? Not so much, IMO.