Ok, that was a little premature. I woke today to launch MM and was greeted by the annoying "Reading Files..." bit that took about 15 seconds to run before I could play songs. Isn't there anyone in an official capacity readingthese posts?
I have had the same problem that was never really solved. My library and database is on a NAS unit and takes an eternity (longer than yours) to actually start. MM3 was a virtual instant startup whereas MM4 starts on plate tectonic times. I have three machines all accessing the music so a completely shared system is perfect. Having three separate setuups is just so much faff.
Despite the MM teams (and I do love them all) claims that MM4 is significantly faster than MM3 the problem was never solved.