As reviewed here, Gene Roddenberry's original pilot 'Genesis II' did NOT air on NBC as you reported in your review, but on CBS. Sadly, as you might know, CBS passed on it, instead going with a 'Planet of the Apes' series, which lasted barely half a season.
I think they (CBS exectuives) would have been better served if they had gone with Roddenberry's project instead, but that, of couse, is not the way things played out.
Two of Roddenberry's failed pilots did air on NBC, those being 'The Questor Tapes' and 'Spectre,' Of Roddenberry's non-TREK projects, I found 'The Questor Tapes' the best.
I disagree with your verdict, and also disagree that 'Planet Earth,' a second attempt at selling the series on ABC was a better product.
I preferred Alex Cord over John Saxon as the lead character, Dylan Hunt.
I do agree that to some degree the films, especially the second one, are dated now. It'd be interesting to see how a modern production would differ.
Incidentally, I found 'Andromeda,' which was VERY loosely based on 'Genesis II' unwatchable, mostly because I find Kevin Sorbo a terrible actor.