That's interesting that each and every style needs to be tweaked individually. Wow, that sounds like a ton of work.
This might be a good time to use what some of the guys on the General Arranger forum call the "easy eight." I believe this started with Roland arrangers when they used style cards that had 8 styles per card that covered all the major kinds of popular music.
I don't know if I could get by with just 8 styles but I'd bet the right 20 styles with good choices for the variations could cover anything a person would want to do. That almost sounds do-able.
I guess one of each of these used at different speeds would be a good possibility: swing, latin, 8 beat, ballad (triplet feel from the '50's), 2 beat (for country, march, polka, dixie, foxtrot, quickstep), rock, disco, boogie, shuffle, waltz. That ought to cover most of it.
That's one thing I think is funny about the arranger keyboard concept. I used to play in bands playing, trumpet, sax, organ, electric piano and drums mostly. Each of the genres we did almost always fit into the groove of one of the styles I listed above with a few variations. The rhythm sections almost always played the basic beat and the only thing that changed was the melody and fills that the musicians would put in. Now I have a Tyros 2 with 400 styles and probably over 10,000 other styles. Really kind of mind boggling when I think about it