I agree with Fifer. A good MIDI file + a good sound equipment can make a very good job. It depends also of the styles and the used instruments. For ex. brass instruments parts are harder to reproduce than strings parts.
I think some early MIDI files of BIAB should need to be reviewed and enhanced to make them sound better. I did the job on some styles I often use, but it's a huge work. Some examples : add enveloppes on strings parts, mainly for attack and release of the sounds, tweak the velocity of individual notes inside a pattern - so get rid of constant velocities on parts ! - , add bass patterns when next chord goes down a 3rd like would play a real bassist, add specific /prefill fill patterns not only for drums but also for some instruments to add intensity in the groove, etc.. delete all grid drums and replace them by live drums, etc...
MIDI is not dated : see the PSR or Tyros keyboards for example, they work with MIDI files as styles.

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