Have you used paredit-mode in emacs with a lisp dialect? Getting proficient with this mode can be a lot like what you describe. Paredit let's you navigate and edit the tree structure of lisp code pretty effectively. It's not inherently a modal paradigm, but I used it evil-mode successfully. I'd imagine what you describe could be a refinement on that technique. Lisp lends itself well to this type of editing due to it's lack of syntax. Other languages are more difficult.