I think there might be some rough edges or polish needed on the new project features before they are promoted.
1: Most important, not all of my projects got converted correctly. The project that I had opened was converted, but none of my other projects were converted correctly. It looks like the list of folders might have been preserved, but, none of the tabs were preserved, and none of the unsaved stuff was preserved.
2: The Save Project As option is almost always greyed out. I don't know why. Personally, it would be way more usable if I could click it and it could give me an error message so I know what to do. If I'm not supposed to use it, then why is it there still? How do I save a project now?
3: It is really not intuitive that the Recent Projects is a menu, but Switch Project isn't and that one opens in a new window but the other doesn't. It's weird to have two different uis for the same thing. I think you should pick one or the other and change the Recent Project menu item to like 'Open Project in New Window'. Additionally, you should move the horizontal line above Switch Project to be below it. It's weird there is a line separating Open/Recent from Switch when they are a logical group. Additionally, think about combining Open Project and Switch Project. There could be a browse button on the popup so that the user can open either a recent project or browse for a project on the file system. Then you are left with two menu items, Open Project and Open Project in New Window.
4: For beta users who won't have converted yet, you should make a backup of their sublime projects for them automatically in case the conversion doesn't work.
5: The Edit Project button seems weird to me. Right now when I click Edit Project it only shows me a json file to edit the open folders. But, when I think of a project, I also think of all of the open files I have associated with it. (Think git5, I have one git5 repository, a ton of branches. I more or less have one project per branch with the open files I was working on in that branch). So, if I go to Edit a project, it is weird I cannot also edit the open files for the project.
6: I would LOVE it, if I could have a single .sublime-project file associated with multiple .sublime-workspace files. The idea is that I keep the same folders open in every single 'workspace/project/whatever', but I have different open files. Most of the time, I want to 'fork' an existing project, but every now and then I'd like to include a new folder in every 'workspace/project', so if I could have one file that lists the folders, and multiple files that list my open files, one for each project, that just point to the file that list folders, I would love you.