TNG used a lot of writers by choice, because it was an episodic show and the writing model back then, particularly for sci-fi, was about utilizing a wide variety of the brightest writers in the genre. It wasn't until the mid-90s, just as TNG was ending, that things in TV and sci-fi shifted to more serialized dramas that required the same writers to work on nearly every episode of the series.
That's an understatement. The market and situation are completely different. TNG was able to endure in spite of two lackluster opening seasons because it was in syndication and Paramount ingeniously required networks to carry the new show if they wanted to air reruns of the original series. It paid off because hundreds of networks aired TNG, even if they didn't exactly want to, getting it into as many homes as possible. In contrast, it's like CBS/Paramount is trying to limit its audience by restricting Discovery to a single outlet (domestically) and charging the end user (rather than the middlemen, the networks) for it.
Also, TNG got good reviews, even in Season 1. This having an embargo on them before Season 1 even starts isn't exactly a great sign.