Oh, there was plenty of negativism toward TNG, particularly from the TOS cast. Most of them were skeptical or openly hostile to the idea, far more so than they were toward ST'09 (though maybe that's because at the time, they still saw it as viable that they could continue in their roles and saw the TNG cast as competition, whereas today they all -- aside from Shatner -- accept the fact that they won't be coming back).
To a large extent, TNG was a reboot, at least initially. Roddenberry tried to keep it as far removed from TOS as possible, avoiding TOS aliens like Vulcans, Klingons, and Romulans, redefining the warp scale, etc. (And when TNG did use Klingons and Romulans, there were a lot of complaints about the show not following the versions from John M. Ford's and Diane Duane's novels.) Roddenberry even rewrote the Trek universe's history, introducing a "Post-Atomic Horror" in the mid-21st century that seemed to be meant to take the place of the 1990s Eugenics Wars/WWIII from TOS. In the years since, we've figured out how to reconcile those different versions of history by assuming that the WWIII mentioned in a couple of episodes was separate from the Eugenics Wars, but that requires ignoring Spock's explicit statement in "Space Seed" that the EW was "your last so-called World War." In TOS, WWIII was definitely meant to be in the 1990s, so at the time, the introduction of "the Post-Atomic Horror" of the 2070s in TNG was a major, major retcon (though a perfectly understandable one for a 1987 production).
It was revealed a few years ago by someone who knew Roddenberry at the time of TNG (I think it was Paula Block) that he once told her he considered much of TOS to be apocryphal as far as TNG was concerned. Just as he'd chosen to retcon the Klingons' appearance in TMP and pretend they'd looked like that all along, so there was a lot about the TOS universe that he wanted to change or ignore, things that he wasn't satisfied with because others had created them or because the budget and technology of the time had forced him to compromise the credibility he wanted. He intended a lot of TOS to be superseded by the new TNG canon he was creating.
However, in the years since, his successors have introduced more and more TOS elements into the 24th-century shows and come up with ways to reconcile the inconsistencies and merge the series into a more cohesive whole (even explaining the Klingon forehead issue). So today, we've forgotten how much of a reinterpretation TNG initially was.
It's what I've been saying -- time softens the sharp edges. We learn to get used to the incongruities, to rationalize the problems, and so they seem smaller to us with the passage of time than they were when they were new. Also, just looking at them from a distance makes them seem smaller and more smoothly blended into the larger whole. So we constantly end up imagining that the controversies of the past were not as intense or numerous or heated as the equivalent controversies that are going on today. And we come up with rationalizations to justify that perception. But the truth is, there's no real difference. There's nothing new under the sun, not where human behavior is concerned.
