Yeah it does have a lot of complex delicate mixing to it. I'll take the opportunity to list other music pieces that I'd like faithful MIDI renditions of.
This track has a similar feel to what I desire from the Killer7 music. Chill but with a contemplative rhythm:
https://www.youtube.com/watch?v=3WZb20NinCs
This track I know could be a MIDI and it may well exist already but I failed to obtain the Windows port of this game:
https://www.youtube.com/watch?v=s4A1Y_Cdwog
Another PC-98 track:
https://www.youtube.com/watch?v=u7DrpEroWV4