I used to be quite harsh with TNG, particularly when it got started, but within the past few years I've softened a lot. I'm one of the few who generally prefers the earlier seasons, particularly Seasons 1-3 and parts of 4. After that I still have no great love for the show. The earlier seasons (as has already been mentioned) felt more connected to TOS in overall tone.
One of the big stumblings of TNG was that the characters weren't that different or distinct from each other. They were near interchangeable. That certainly wasn't true of TOS. Having no friction amongst them was also a problem since the drama and conflict always had to come from outside. I get it was supposed to be a depiction of evolved humanity in the far future, but to 20th and 21st century audiences it doesn't come across as credible.