I'd like to be able to specify a setting for a Smart Sync'd folder that, after some period of time, "releases" the local files back to "Online Only" status. Or alternatively (or in addition), a setting to put a local storage limit on a Smart Sync'd folder so that it can't grow beyond a certain size.
The scenario I would like to support is for frequently accessing large (10s of TB) amounts of disparate data, hosted on the server. Being able to "see" these as local files would democratize data access workflows for workstation users that either don't have development experience, or just don't want to have to bother developing against the Dropbox API. Common scenarios would be for accessing video assets, and for churning through data analysis (Python, Matlab, etc), among others.
The cap and/or timeout would mitigate the issue of running out of (limited) client machine storage, but still 1) allow for both ease of access (a "local" file with no specialized access needed), and 2) provide the temporary locality/caching needed for efficient data access. This would be a game changer for my business, and would motivate a subsription from Business Standard to Business Premium for my SMB (~20 employees).