Let's not forget Enterprise. Though it started as episodic, it ended up serialized like DS9.You are free to think however you want, But DS9 easily had the most developed and intricate story in the franchise.......it's not even close. The other series were in fact DESIGNED to not have significently complex stories, favoring a episodic approach.
Well, yes......for a considerably shorter period of time, and in a somewhat half hearted attempt to improve meager ratings. I don't think it makes the grade next to DS9, although I'm glad it was mentioned. It was at least an attempt of later trek to go towards serialization.