said, Sisko is 100% human.
I personally dislike Section 31, as its led to some pretty daft fanwank ideas about how to use it for future series, especially when its something so covert and secretive that only a handful of people know of its existence.
I don't get the hate about Ezri. She was a nice character and an interesting idea that helped give things another little shake up in S7. Yes, she was give a few episodes to develop and flesh out her character, but she didn't take over the series (like another female added to another Trek show). I personally would've liked the character to be male, just to have them really mess with the likes of Worf, Bashir and Quark.
Section 31 aside, there isn't anything I find "stupid" about DS9. There are things I would've liked to have seen, but a few little bits here and there that I'd have liked done differently, but (to me anyways) DS9 is Trek at its very best.