I know it's been a while since this thread started AND that I'm trying to play on a "not exactly supported" platform, but this still might be interesting enough for people to contribute.
So here I go:
I installed Arma3 via Steam on my mac and the game runs perfectly (!!)
The only problem is that it does not recognize any mods downloaded from the workshop.
I don't think the launcher is supported on Mac, since it requires Windows OS components.
I am trying to figure out a way to run the app the same way as above, with parameters pointing to were the mods folder is.
Can anyone help?
Thanks!