What I miss is that the main protagonists, which I always considered the dragons, are of more use than just fighting the spores. They are what makes Pern special, but if you think further ahead... as soon as the spores won't fall anymore they'll most likely have to disappear themselves, or otherwise be hunted down and destroyed for ages to come, since they'll be of no further use and on the other hand "cost" way too much.
I also found the idea of the spores itself a bit bizarre, and I wonder what exactly causes their existance and fall onto Pern. Maybe I missed that information, though. I lost interest after Dragons Dawn, which is one of my favourite books of the series, probably since it did explain most of what I was wondering about and I didn't expect any big surprises in the following books anymore.