+1 for Expression/humanisation. I already sent a post in this way some months ago.
Randomly alteration of the start/end time of individual notes is fundamental and should be extended to all the tracks, with independent settings per tracks.
Light alterations of notes velocity should be also applied to the tracks, to avoid that the same pattern of a style is always played in the same manner.
Without these features, BIAB generated music will ever feel mechanical.

Reach for excellence