It would take many pages to comprehensively explain what is good (and bad) about Bewitched, so I’ll try to keep this brief, and apologies for the points I don’t touch on.
First off, the influence Bewitched has had on popular culture cannot be ignored, it was a significantly popular and influential work, and not just in regards to the magical girl and magical girlfriend genres. It was certainly not the first supernatural sitcom, but it was one which popularised it, taking it in a new direction and many later shows took cues from it, even into the 2000’s.
Values dissonance can cover about half the complaints. As for the rest, people tend to forget that Bewitched was in part meant to satirise many of the deeply conservative attitudes portrayed in the show, i.e. Darrin being the personification of conformity, his opinion of witches and Endora’s contempt for ‘mere mortals’ and other characterisations give alarmingly realistic parallels with sexism, racism, homophobia and snobbery. Moral guardians of the time would have likely stopped the show making the satire more obvious. Well, that, and the fact that any Aesop learned would be forgotten about by the next episode (continuity was never this show’s strong point).
Overall, bewitched is a great show that could have gone further but unfortunately did not. The writers exhausted their originality by around seasons 4-5. Character development was fairly alien to them (flanderization wasn’t though), and they had basically given up trying by the start of season 8. A shame, considering the many exiting things they could have done with a premise such as this.