So TNG was beyond bad, yet some episodes were genius. And all Star Trek movies are bad, yet some are entertaining because they are Star Trek. But Star Trek is very very bad.
It's all so confusing. 
Maybe it will help to read more carefully and not reinterpret what I said. Apparently you don't know that the first season of TOS was extremely cheesy and had very low ratings. It was almost canceled in the second season and then canceled in the third.
Then they decided to revive it after the success of other SF in general. They made a movie. It didn't do as well as hoped but enough to make a sequel. They made a whole bunch of movies that were popular enough. These movies are typical Hollywood movies. They received mixed reviews.
So then they made TNG episodes. Now these episodes are something else. The first ones started off kind of bad and silly, like the one where everyone goes into a sex frenzy. But once the good ones start you can't even compare it to what the movies did. It is something totally different. They ar extremely low action oriented, based on dialog, plot, exploring interesting ideas. They are about philosophy and morality. This is by far the highest rated ST series and received several awards like Emmy's. This is the big success of Star Trek. They made movies basedo n TNG but Picard in the movies is like the opposite of Picard in the series. These movies have even lower rankings then the TOS movies.
Then come DS9 and Voyager. You can compare them with TNG but they are just not as good in all aspects. Therefore the series slowly went downhill.
Very bad movies van still be entertaining. You want to see a TNG movie because it is based on the series and finish it no matter how silly the plot or bad the acting. And they can still have entertaining moments.
So yeah TOS series I would rate 5.6. Movies TOS I would rate 6.8 for the good ones and 5.6 for the bad ones. TNG I would rate 8.8 with up to 9.8 for the best episodes. TNG movies I would rate 5.5. DS9 and Voyager I would rate 7.5. Enterprise I would rate 6.0. The 2009 movie I rate 2.2.