Ok, you folks have used arranger keyboards. Which means you're looping some background tracks that swap to a new chord on a particular bass key,chord type pick.

What do you think of these sort of things?
- auto octave: on a LH note, autogenerate a note an octave below, same velocity. Optionally, use the velocity of the note to add further octaves below.

- auto arpeggio: Hit the bass note, then just use 2 keys next to it to generate the notes for the rest of the arpeggio notes (picked by LH track the sequencer has). The note is auto-picked, but the velocity is what you play on the "wrong" key.

- auto glissando: smooth pitchbend from last note to current (in say LH)

- auto RH 3rd: add a 3rd above RH note for all RH notes in sequencer's RH track.

Do these things sound useful? Do they seem too "cheat-ish"? Given a sequencer with RH and LH piano tracks of the song labelled RH, LH. The rest of the tracks playing in background velocity scaled to what you're playing versus RH and LH tracks' note velocities.