As far as I know that has a bug in the Mac version that was never fixed, where you can't install the Warcraft 2 files. You'd presumably be able to use Wine to run the Windows version to extract the files to use with the Mac version, but honestly it's simpler just to run the original in Wine.

You don't think they would be able to avoid a lot of duplication, if they just remade the engine in windows and not touch the game files for maps/sounds/animations?

A lot of games especially earlier ones still will rely on the iso rather than having it as a separate product. The fewer targets you have to make changes for the better.

I can’t think of a single example, but I do not play a lot of games from this hybrid DOS / WIndows era so that might be a common practice that I missed.

For Warcraft 2 the Battle.net edition never included DOS support, so even the full disk image would not help. Anyway it is not included.

I think for playing Warcraft 2 on Mac OS (or Linux) the best suggestion has been shared by Kobi-K already: the open-source Wargus engine.

It's more, a known format for them and already mastered, why change it? The gameplay doesn't change, only where the window displays, thus the engine could just be recompiled with some GUI addons to make it windows compliant. How hard that is, i am not quite sure.

I have a compressed WC1/WC2 Dosbox archive that's ready to go. (Though i couldn't separate out the music to compress as MP3 to make it smaller, ripping those out leaves you with midi-only. Also had issues with Dark Sun's CD music); I'd wager changing the DosBox program call would make it work and run; But this is a guess, as i don't own a Mac to test it on.

No, the Battle.net edition of Warcraft 2 is not the same as the DOS version. The gameplay is in fact changed (various control changes such as being able to use control groups, bug fixes with unit behavior and so on) plus there are new sounds, etc. It's not possible to use the Battle.net edition with DOSBox at all. Really the best way for Macs is Wineskin/PortingKit/etc. I tested in Wineskin, just install and run, works flawlessly. If you use the Warcraft II option in the launcher, as opposed to Warcraft II Classic, I'd recommend using a real 4:3 screen mode like 1024x768 or so (the upscaling with 1440x1080 is a little weird), that way the mouse is constrained to the play area and can't go in the black borders. I seem to recall reading something about the latest version of the OS has removed 4:3 screen modes by default, but you can add them back with a utility such as SwitchResX or others.

If you have the original game, it can be dosbox'd manually. It's doubtful that any such official bundle will be made though.