2nd season was unbelievably bad, like Lost In Space times the worst of VOYAGE TO THE BOTTOM OF THE SEA, only 'embellished' with vfx courtesy Hanna-Barbera (technically that last part is true for all 3 seasons.)
Anybody remember the S2 ep where the sub is used for time travel, I think into some alternate future with just a couple human kids alive? I was waiting for Bridger to say 'When this thing hits 88 knots, you're going see some serious shit.'
Then again, Scheider wasn't shitting us when he said that season was going to be childish.
I think there were maybe 4 or 5 s 1 eps that showed real potential, and I though the very early one where they find the 'loading dock' for the library at Alexandria was actually a winner on all of its plot threads, and Bridger really came off very Kirk-like (in a GOOD way) when he threatens to destroy all those treasures if these assholes don't get their ducks in a row yesterday. I've probably seen that one ep 15 times (14 on VHS!) ... but man, such wasted potential.
I almost got to go on the sets early first season for an article, and I still wish that hadn't fallen through. Somebody in Amblin' PR kept jerking the editor and publisher around on the date I was supposed to go, and finally, about 48hours before I was going to fly down, another joker at Amblin had the nerve to ask the editor and publisher about their bona fides. The reply was something akin to,"you know that MAKING OF JURASSIC PARK book your boss likes so much that he actually put it ON CAMERA in the movie? Yeah, we're the ones who wrote it, bye asshole.'
Even after it fell apart, I had a really good correspondence and phone conversation with the original production designer, who was impressed I noticed the lack of lips on shelves (to keep everything from falling on the floor when the ship swerved) ... apparently they had all that designed in a more credible way, but those finishing details got left off (I think he had already left by then to do Earth 2 for Amblin.)
I remember an ad or commercial like you describe from when I was a kid, but that would have been 20 years before seaQuest aired. It was a very rich evocative thing, a family looking out to sea or to the horizon as night fell, but obviously not the promo you saw.