As a newbie to Metabase, I've been looking around for a solution to these synchronisation problems, only to find that no official ("proper") solution exists. As I've stated here, Metabase is a great product, but import/export functionality is a requirement for serious development and large-scale deployments.
I'm not sure many new users actually come from a background that would immediately require such functionality. But as the company grows, these features soon become essential. The lack thereof is only feasible if
- the database isn't particularly large
- there's only a single person working on the Metabase db (no need for git-like branch management, at most one development instance...)
- there's only a single production instance running
If these conditions are met (which would be very rare for large companies), then I can see why the current feature set of Metabase would suffice.