"The biggest problem, is the fact that there is no easy way to create song specific user styles"

Bachus, have you tried the midi-to-style converter after the update on the PA4X? If you have a good midi file, it's quick and easy to make a pretty good style. Yes, you usually need to do some "tweaking" after the conversion, but it's easy to do...adjust some style part volumes, maybe change to factory sounds from GM sounds...
I'm personally a little leery of using too many song-specific styles. I can nearly always find a style that will work, then play the intro and signature riffs myself. That way you stay true to the song, but still "make it your own".