So pretty much any restaurant on the Disney property has had someone not like it. I think you can say that for ANY restaurant anywhere. Someone is going to have a bad experience by their perception or not enjoy it. It happens and WDW restaurants are no different. Are there some that get worse overall reviews than others? Absolutely. But for every bad thought about a specific restaurant, there are others who do enjoy it and maybe had a better experience. I also think thoughts about them can be jaded because expectations are built up and then when someone is on a once a year or so trip they get let down or in converse they get surprised. I go a ton and have TIW and an AP so trying different places is something I enjoy and like most locals or people who go a lot have a larger sample size to work with because most places I have tried more than once even if they let me down the first time. Others, now that I have been twice, I just wont waste my time with. The old addage go where the locals go applies. Try places that for the most part of the "regular" visitors go and say its good and you generally will not be let down. As a regular visitor there is a list of always worth the stop if its convenient, always worth the stop no matter what, and Wont ever walk through the door again. The changing Chefs at the restaurants also highly effect the food. Jiko, Cali Grille, Flying Fish, Yachtsman, Monsieur Pauls are all examples of this.
The only absolutely will not do again places on our list are: Grand Floridian Cafe, Beaches and Cream, 50s, ANY counter service in Studios, ANY Sit down restaurant at MK except Skipper or Castle breakfast for a special occasion, Chinese or Japanese sit downs in World Showcase, Biergarten, Artist Point, Edison, Any Buffet other than Boma, San Angel, counter service American Pavillion World Showcase.
Our restaurants that we generally have no issues with and in order 1-10: Il Mulino, Tiffins, Cali Grille, Jiko, Flying Fish, Boathouse, Yachtsman, Narcoosees, HBD, Citricos
Others we will go to but can be hit or miss is a huge list.