Who are some wrestlers in NXT that have the best chance at succeeding in the main roster, and some wrestlers in NXT who have the worst chance at succeeding in the main roster?

An obvious choice for the first one, I think, is Kendal Grey. She can't talk very well, but that hasn't stopped Stephanie Vaquer who's not the best promo in English from being incredibly over for her ring work. Kendal has a great chance to be someone on the main roster.

As for worst... He's definitely not the worst wrestler there, but in terms of how much he's valued in NXT, I think Tony D'Angelo will have the biggest fall from grace unfortunately. Tony is someone that I think is a good example of why the territories getting killed was such a horrible thing, because someone like him could work in a major American promotion that emphasised goofy or silly characters, but there's nothing resembling that I think as of now. WWE has a few goofy characters, but they're almost treated as separate entities entirely who very rarely matter in the grand scheme of their stories.