Is Renoise suitable for midi orchestration ?
I like the price, and multi plataform support.
But, what do you think about the tool for heavy midi editing?
Thanks!
Heavy MIDI, not black MIDI? 
Jokes aside, Renoise is not really a MIDI focused DAW. Yes, there are definitely people using Renoise for this kind of thing, but you have all sorts of commands that doesn’t have a MIDI equivalent, and entering good ol’fashioned MIDI commands in the pattern is a bit quirky.
You can come a long way of course with MIDI device automation, and then there are all the other advantages - sample manipulation, and tracker workflow.
But I would simply give it a shot (try the demo) and see how well it works for you?
Admittedly I have no idea what you mean by HEAVY MIDI editing, but I just want to give a shout out to a beautiful orchestral sound bank I found online.
https://github.com/jbbourgoin/renoise-instruments/tree/master/Sonatina
I have gotten a lot of mileage adding these gorgeous samples to my (mostly rock, hip hop, and dance) songs. One of the things I like best about Renoise is that it’s easy for people to create and share sound banks that open up a world of free sounds you can add to the tool.