Bayley has done well since her Sept '14 match against Charlotte at Takeover, and the rematch with Charlotte a few weeks later which I thought was better than their Takeover match. Her character went from 'aww shucks, happy to be here' to 'I'm happy to be here but I also want to win'. She delivers nice rants when she's on television, she had good matches with Becky and Sasha, she put a bit more 'oomph' into her offense (and two nods to Sami Zayn... suplex to the corner and a diving baseball slide similar to how Sami does the spinning DDT)... she's good. And she's only going to get better. Now that she's champ she could evolve even more before she heads into the main roster and gets fucked over. In NXT, I can see her having nice rants off between her and Emma, Dana Brooke, Carmella, Alexa Bliss... the sky is the limit. Bayley and those four could practice FOREVER in the performance center until they get their psychology of the match down pat and give the fans a nice match at upcoming Takeover's.
Bayley/Eva Marie would be another $$$ match up. but unlike Dana Brooke, Eva Marie had some training and went straight to main roster and Total Divas. There's nothing wrong with that. But someone realized 'Damn, we invested a lot in her. What can we do?' And the 'can we do' is putting her back into NXT so she can get better. Which is good. Because NXT could always use more women. And Eva Marie can get better... she was an athlete in college. In 2-3 years she can be a valuable asset just like the other women.
My selfish desire is I'd want Bayley to stay in NXT forever and bring Charlotte, Becky, and Sasha and just have some great rants and feuds. But since that's not logical and not gonna happen anytime soon, I really hope Bayley can feud with Emma/Dana/Carmella/Alexa Bliss before leaving. Maybe even have a match with Leena (Nia Jax) before leaving. It would be fun to see Bayley's character get completely walloped in the ring and see if her character can turn the tides around against Nia.