Series 8 was better than 7 because it returned mainly to the old premise of Rimmer and Lister stuck back together again; the entire concept of the show from day one. I was appalled the first time I saw series 7 and 8 but over time and from rewatching them, especially with the DVD commentaries, I've found merit in them.
The best series are I and II, with Marooned from III thrown in. Kryten sticks out like a sore thumb as a revival piece in series III, but eventually comes into his own. By VI they had a great team dynamic going, and even though the concept of the show had completely changed from the first two series (almost unrecognisably so), the plots, dialogue and characters had all fallen into place. Such a shame Rob Grant left, and a real cop-out over the way the whole nanobots thing turned out, resurrecting the crew and everything, it just seemed like another show revival technique, with series VII providing a stop-gap.
It would be great if they could get everyone together for a feature-length special or three-episode series and take it out with a bang, but the actors are all a decade older and any explanation for the fact would probably seem contrived.
My suggestion is to read the two books that pretty much finish with all the loose ends tied up, and imagine them as films. And what awesome films they would have made.