Have you tried https://github.com/EugenMayer/docker-sync ? I've had slow FS issues with docker on mac. Integrating docker-sync doesn't take long and should help you out.
I haven't, but I recommended it to one of the devs and he claimed it 'crashed' docker. Need more investigation, but we shouldn't need tools like this; it should work by default.
Agreed, and to my knowledge this is a known issue (I'm sure I've seen chatter regarding the problem on the docker forums/github). Nonetheless, with docker-sync I've been able to leverage all the benefits of docker-compose whilest mitigating those slow mounted fs issues, so for now I'm happy with it. At least you can configure it directly into your compose set up, so you don't need to spend time explaining it immediately when onboarding those new developers.