In my opinion, score means nothing unless you fly a single aircraft series, and its varients, for a full tour or more.
Just how you rate against others is really dependent upon what you fly, and against what you fly, how well you fly what you fly against those flying against you in various aircraft, and their varients, your understanding and execution of BFM and ACM in your aircraft vs others in their aircraft, and how well others counter your moves utilizing BFM and ACM in the aircraft they fly against you.
That's just the fighter/JABO aircraft side (and not well defined).
For the GV, Bomber, Bomber Torpedoes, PT rockets and or torpedoes, GV Capture, Goon Capture...it's pretty simple...but dependent upon how well you can read a map (when and where can you execute safely)...and how much you really want to score well overall...and this is the area where the greatest amount of scoring (i.e. the reduction of score) takes place, overall. How do I know? I've done it.
If you want score to mean something, make it personal.