Bill maybe Roland dropped it because the style composer is much more sophisticated.

Here are some things you may not have tried..

First you could record your song as a midi data (style play) save as a SMF.. load into a midi editor (GNMIDI) select humanize and resave the SMF.. If you like the not up to par drummer, or bass player. it is perfect for that average band sound

The better way, use the Rhythm composer.. My example is the G70 but most likely everything is also on the BK9 (although the G70 is faster to use). Most styles use 4-8 drum patterns in a style.. for a 3 minute song it is usually enough.. but the G70 (maybe the BK9 too) can use 54 patterns in a style.. A pattern can be assigned to the 4 variations,6 fills, 4 intros and 4 endings. You can however assign a pattern to a specific chord (7th) this combined with a punch in record of a 3 or 4 note walking bass can make all the difference for lead into chord changes..

Another composer option "shift clock" .. you can have the drummer drive a bit or maybe the bass player lay back a bit..

And copy from another style any arranger parts at specific locations... you can make your style sound the way you want the band to play..