One of my biggest issues with the way they ended DS9 is the way they left the Ferengi homeworld.
I would have totally believed if Quark went to Ferenginar 100 years in the future and saw a world where women are equal, the unemployed get welfare, monopolies are illegal, and all that other good stuff.
But over the course of one year? Really? Profit and Lace showed a law change that made it so women can earn profit, okay. Jumping from that to it being fully accepted in Ferengi culture almost immediately is a huge stretch.
And then, making Rom Nagus? Yeah, it was 'feel-good' ending. But I imagine the Ferengi stock market tanked completely about two days after that. Progressive reforms are awesome but if you try to apply them without really planning them through there's going to be a ton of unintended side effects. Part of implementing progressive reforms is having the maturity to know where to stop them, and there is a difference between what feels like the morally right thing to do and what is the effective thing to do.