AFAIK the plan is still to release a Mac and Linux version of Dragon Commander. The engine is being ported for Divinity Original Sin, so after that game is released (June 20th) Larian will be able to do Mac and Linux versions of Dragon Commander, as well (presumably after a bit of a break).
Larian said they had some additional updates planned for Dragon Commander, so they may want to add more stuff for a Mac/Linux release.