"Go to definition" and "find all references" would be awesome.
Oh man, I was just about to make a new post about this. Currently, the only way to really do this is super tedious/ghetto -- You need to export your files, unzip it somewhere, open up Notepad++ and "search through all files" for what you're looking for:
Would LOVE a reference finder for vars/funcs. This would further allow us to be more encouraged to optimize code. Currently, when I find better optimizations, I'm terrified to touch anything in case I miss a reference. And afraid to remove deprecated code that may be bloaty.