I wouldn't
completely rule out another film sometime in the future. We know what the film industry can be like. More likely
not, but I couldn't 100% assure there wouldn't be another TLK film, even if they waited until twenty plus years time. As much as I like to keep seeing the characters 'active', I don't think yet another film would be a good idea. Enough is enough, don't taint the quality of the originals, etc. - these things that the movie industry don't seem to consider when there's dollar signs in their eyes.
Perhaps a film which included the hyenas would have been good years ago, and I did say in another thread that when I imagined what a TLK sequel would be like I was even thinking 'The Hyenas' Return' (at least I was highly accurate about the
Jungle Book sequel
). However now it would just seem like more milking of the franchise. Really, the only way the hyenas could have a film is by them returning to cause mischief or something - anything else would be stupid, and even that could be handled rubbishly.
If they did plan to do another film someday, whether about Mufasa and Scar as children or Kiara and Kovu's cub/s, they'd better darn well put a looot of effort into it.