1) I do a lot of programming work in DB so I can easily go back to earlier versions of my code development, which for me is very useful. But there is a lot of conflict between DB & my development system trying to access the files at the same time, causing numerous errors in file access. I have no control over where the output directory of my compiler puts its compiled output, so it all ends up in my DB. In addition, there are a lot of intermediate files (like *.obj) that have no need to be backed up to the DB cloud which just wastes my (and yours) DB cloud space. There is a "Make online-only" option for a file/dir but no inverse. I'd like to see a "Make local-only" option in the same dropdown list as "Make online-only". The Power Shell cmd "Set-Content -Path 'C:\Users\yourname\Dropbox(Personal)\YourFileName.pdf' -Stream com.dropbox.ignored -Value 1" seems to be one way to do this but I've not yet been able to verify how effective it is. Seems to me if the Set-Content command works well this option would not be difficult to add to the dropdown list since the Set-Content option is a bit cumbersome and not well-advertised.
2) In addition, I'd like to see "Make Type local-only" option to make certain file type lists like *.obj local-only in specific or all DB folders to save space in the DB cloud. Since files like *.obj get regenerated frequently the Set-Content option above is not practical. This capability could be added to the Sync Tab in Preferences.
BTW: I had to upgrade my Power Shell to make the above Set-Content command work. That should be added to your How to set a file or folder to be ignored - Dropbox Help page if the command generates an error.
Matt