If you start Sublime Text without any documents passed to it, that is a blank window, and then use any of the 'Open ...' dialogs you get different starting locations.
'File - Open File...' or Ctrl+O and 'Project - Open Project...' both open to the default installation directory for Sublime Text.
'File - Open Folder...' , 'Project - Add Folder to Project...' and 'Find - Find in Files...' or Ctrl+Shift+F open to the last location that an 'Open ...' dialog went to.
Making them all, without any prior direction, open to the same location, preferably the user's home folder, would be a more consistent and less confusing experience.
Then, once some activity within the editing pane has taken place they could follow the user's desired path.
ie. If the first file opened was in directory A the subsequent 'Open ...' dialogs would go there first.
The logic being any further files you add or files you search would more than likely originate in the same location.
Opening Projects may be slightly different depending on your view of where Projects should reside. I like mine in a dedicated Project folder but I see others like to have them in the same directory as the files they relate to. Since 'Add Folder to Project...' would logically want to add folders from near the starting location of the Project that dialog should follow the path set out in the project. So for consistency maybe 'Open Project...' should do the same.
So unless activity within the editing windows provides indication of the location to use, ALL 'Open ...' dialogs could first open in the user's home directory.