Realistic Midi.... almost an oxymoron.

But, depending on the instrument, how well you understand how to program midi, and knowing the nuances a real musician who plays a given instrument would use... and having really great, sampled, sounds...... it's possible.

Drums, bass, and piano tend to be the easier to use and make sound real. Woodwinds, and brass, and stringed stuff like guitar ..... not so much.

BUT.... technology is improving all the time and there are some great sounding sample libraries on the market. Just don't expect to get a really good sounding sample library on the lower end of the cost spectrum. The good stuff costs money....and generally, lots of it.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.