To each their own--I loved TNG a lot back when it was first on and time has done little to change that opinion--in fact having about 15 years worth of television under my belt since then I still think it holds up extremely well and is a great consistent series.
You've got the right word, there - consistent. The thing about TNG is that, even as the episodes rise and fall in quality, there is always, consistently, an extremely competent level of production that includes acting, writing, directing, and pacing. That consistency makes the series extremely watchable, even if an individual episode's plot is sub-par. That's something that isn't being made clear in Warped9's reviews, obviously because he does not share that opinion, and that's why his reviews have been skewed lower than, I think, the episodes actually deserve.
Warped9 seems to be, at times, criticizing the comfort level that TNG had reached by 5th season, as if it's a criticism. But Star Trek has always been successful based almost entirely on the level of comfort it instills in the viewer. This is not intellectually challenging hard sci-fi we're talking about here, or risky heavy-hitting drama. TOS, even at its best, was great precisely because it was so easy to watch, so comfortable, so likeable - not because it taxed the brain, or the emotions. By literary sf standards, City on the Edge of Forever, Space Seed, and Trouble With Tribbles are lightweight throwaway sci-fi plots, done, and done much better, in dozens of stories published previously since the 30's. By comparison, both TOS and TNG are, for the most part, extremely simplistic.
What they do have going for them, though, and what makes them among the 2 best sf shows ever produced, is their likability, their approachability, and their comfort. And that comes from creating great characters, casting great actors to play them, and giving them entertaining things to say. That takes good writing, of course, but only good writing of a certain kind. I love Ron Moore, but he's not Isaac Asimov or Greg Bear. These shows are fantastic, yes, but they're fantastic because they're easy, predictable, formulaic fun. They're charming as hell. They're exciting for all the obvious reasons. They make us want to live in that universe. (And for all the press on how dark DS9 was, that show ultimately succeeded too for the same reason - DS9 was a place we all kinda wanted to visit, and have a drink at Quark's, maybe play a dart game with Miles and Bashir...)
So, to complain that TNG had become formulaic and comfortable is to complain that it is Star Trek. It is nostalgia and nostalgia alone that makes anyone think that TOS, or in fact most of the franchise, had anything going for it more than that, it's intense likability. Now don't get me wrong - likability is not an easy characteristic to evoke. Very few shows have done it as successfully as TOS, TNG, and DS9, which is why they're all great television.
And also, don't mistake me for an apologist for bad writing. The 5th season of TNG is clearly a weak one, and the first third of season 6, up until Chain of Command, is more experimental, but hollow and silly. The first 2 season of TOS are clearly better, on the whole, than its third. There are levels of quality here, to be sure.
But my point is, TNG's consistency made most of its episodes at least very likable and watchable, Star Trek's primary asset. A mediocre TNG episode, for example, is far more watchable than, say, a mediocre X-Files episode, or a mediocre Voyager episode. Even the bad TNG episodes, much like the bad TOS episodes (and they can be very, very bad) are still better television than bad episodes of most other sf shows produced before or since. That's why these string of 1-star reviews for TNG episodes is just silly. Transformers 2 and Lady in the Water are 1-star. Let's keep some perspective here. A failed TNG episode is still usually at least 2 or 3 (on a 5-star scale, of course), because of, as I said, that one asset the show had in spades: likability.