WWE seems to care a lot about mic work to sell a story.. Sasha, Bayley and Becky don't have that.. Sasha is not as good in the ring as some people think, but she's still not bad, but she doesn't have the verbal ability and character to be a top star. That Boss gimmick is so stale at this point.
Bayley they fucked up since she debuted on the main roster.
Becky is the most over woman in the women's division. I don't think she's ruined quite yet because her popularity is still there. Fans haven't given up on her like they have Bayley and Sasha... Becky is someone who needs a push on Smackdown. She has all the talent in the world.