I agree that lots of the Niven/Pournelle stuff would make great movies.
The Moties are fascinating because they aren’t your standard boring “good aliens” or “bad aliens.” They’re so different they don’t really fit either category.
Although you sure wouldn’t want them moving in next door. You think we have an illegal alien problem now!
My least favorite thing about Star Trek is that you took an actor, put a crinkle in their nose or pointed ears on them, made them exemplify a particular human trait, and they were an ‘alien’. They at least tried to explain it as some intergalactic brotherhood created by the “Founders”; but it bothered me that the men aliens acted like men, and the women aliens acted like women- and they were exactly like humans except for one particular trait was exaggerated.
There are lots of books with the potential to make great movies, but I'm not sure if I'd want Hollywood to touch them. Examples: Any Miles Vorkosigan book by Lois McMaster Bujold and the Kris Longknife series by Mike Shepherd (aka Mike Moscoe).
I can think of one big exception to the "great book = bad movie" trend. The BBC made Terry Pratchett's "Hogfather" into a miniseries that was AWESOME. The actors were all great picks (with Terry doing a cameo as the toy store owner) and the actress who played Susan was perfect. My only minor disappointment was that Death wasn't voiced by Christopher Lee, who did the VA for the animated "Soul Music."
I think it's available for sale now; it was on BBC America around Thanksgiving last year. It was an incredibly well-done adaptation.