Replace the import wizard with Power Query
Instead of using the outdated import wizard (not the new one that was released recently in SSMS), a new one should be created that leverages the Power Query engine (aka the M language) to import data into SQL Server.
This would be huge.
In my opinion, this would have been a quick win that should have been done before the Common Data Model PQ project. That said, I do recognize the amazing potential for the new incremental load features and PQ within a browser.
Koen Verbeeck commented
Regarding data source credentials: this is now also possible in the import wizard (it's stored and encrypted in the SSIS package). Anyway, the end result of the query (or queries) should be a set of tables that are loaded into SQL Server.
Nico Jacobs commented
But since this wizard is based on SSIS, that would mean we need a Power Query source in Integration Services data flow... already hoping for this since a few years!
Problem would be how to leverage the true power of Power Query, where one query can reference others, where to store the data source credentials etc.