Currently share functionality works for single datasets; there’s no share URL to view multi-datasets maps. I guess what you need is missing (could be a candidate for a new feature).
We would need to assess Community interest/need, and figure out if we can get a good pool of money together to fund the development if nobody can step forward to do the implementation.
Perhaps start a poll in #feedback for a #feature-request to see if we can reach critical mass on this one