An idea for 5) could be to have an option to cache ident reply and reverse dns for ips for a set amount of time
What I meant for dynamic symlinks scripting was the possibility to have virtual directories with dynamic properties, like music genre symlinks with correct size properties. So parent dir can have size property as the sum of size of subdirs. And virtual links to files, E.G every song containing 'blabla' in title.
btw. I think you're doing a great job with ioftpd! It's greatly appreciated!