I realize RStudio doesn't lack for ideas but its worth a shot 
One of my favorite features of vscode and Sublime Text is having a project/folder navigator on the side - I often end up using them concurrently with RStudio as I tend to find it easier to navigate through my scripts that way.
I would really like to see such a feature added in RStudio - may it could work similar to the way the document overview works on the sideline
There is a file navigator in RStudio, but you mean one with collapsible folders, right? (I haven't used the tools you mention, so am just guessing.) If so, it looks like Yihui requested it a while back (as "a tree structure") and they did add it to their internal issue tracker (well, "feature suggestion list").
Btw, I think the topic would be better with a more descriptive title.
Yup that’s exactly what I had in mind
We do indeed want to overhaul the Files pane to give it a more traditional tree view in the future. While we haven't yet allocated time for this particular work, it is on our radar!