Sorry for trashing your favourite Treks, but you are just so, so wrong about everything post-TOS.
In my opinion, Trek doesn't get any better than Next Generation, around seasons 3, 4, 5 and 6. I have little patience for DS9, and even less for Voyager. Enterprise I refuse to comment on because I try to follow the 'Voldemort principle' with regards to it; it shall not be named, lest we invoke a curse upon ourselves.
Next Generation was Star Trek, updated. Sci-fi with a humanistic message based on characters and tension arising from the story. Not technobabble, mindless action, or special effects taking the place of storytelling. Next Generation was the truest Trek there ever was.
Voyager was a window into the minds of soulless TV executives who were trying to milk as much nerd-mileage as they could out of a promising idea, and it ended up ruining everything decent about Star Trek.