It's no different than when we used to play in a band, right? All we had control over was our kb parts, and the rest was done by the band. Well, today, it's a cyber band. During any given performance I'll utilize manual bass, auto accompaniment, sequences, drum tracks, MP3/Karaoke tracks, or straight piano (usually Rhodes). The pulse of the room determines the "fullness" of the band. Very often, if I'm using the arranger, I'll mute everything but bass and drums, so I have a clean, intimate trio sound. I like that. Then, as the tune progresses, I might add in the 5 acc parts. (I have a dedicated button that tuns them all on/off)
Very effective. In intimate settings, with small crowds, I find the arranger to be at it's "hokeyest" (is that a word?) when there's 7 parts playing behind my already full chord arrangement. Thinning out the arranger is ver appropriate in these cases.