Is this on the path to be able to work on Catalina, or is it going to go Windows only ?
I've read GOG is updating thier dosbox and other things to adhere to MacOS guidelines, but I checked Wasteland 1 today and it's still not working.

I'm not an expert and I don't have any inside information, so I could be wrong, but this is my understanding:

The GOG version is not actually just the original DOS game running in DOSBox/Boxer, it's a re-release from 2013 in which InXile actually put a custom wrapper/shell overtop the DOS game in order to integrate the paragraph entries. This is bad now, because I don't think it will be possible to play the game at all on Catalina anymore, so most likely GOG will be switching the game to Windows only once they realise this :(.

If you can somehow find the original DOS version somewhere (not "Wasteland 1: The Original Classic" which is the re-release) you may be able to get it running in the latest DOSBox yourself (I have not tested this).

InXile is working on a remastered Wasteland 1 game (similar to what they've done with "The Bard's Tale Trilogy"). The Bard's Tale trilogy has been promised to be coming to Mac (they are working on the Mac version right now), but no official word if the Wasteland 1 remaster will be coming to Mac or not.

Yes, over top of with the original files still there. No, you can use this "Wasteland 1: The Original Classic" to run it. In fact GOG version has a few game crashes fixed vs "raw" version. According to drinnen, you need to move the contents of rom/data into rom (Show Package Contents). Then mount that in a DOSBox of your choice. All too likely seemingly. GOG should simple note that it's not compatible with Catalina instead of not advertising there is a Mac version available.