Great to read you are proposing a GSoC project for the Text Editor. Thank you. There are plenty of Blender relevant features in those BA add-ons you linked to which should be built-ins, imo.
Feature I’m dreaming about is autocompletion made with automatic dropdown list. Like in any other IDE. Without nedd to hit autocomplete hotkey for that every time
it has been already built by Jacq as addon for 2.7X : https://github.com/JacquesLucke/code_autocomplete, I don’t think it has been updated. The best way of getting autocomplete today is probably https://github.com/nutti/fake-bpy-module and external IDE.
Blender bpy is tricky to autocomplete, as this is binary/library file. This is not a thread to discuss this so I will end here.
@Poulpy, the feature that you can start from, is add abiity for blender to create fake bpy by itself (ex. parameter in command line). The benefit is easy to start development in external IDE.
This sounds great. I also wish that someone can address the “undo” issue. For instance make some changes in the text editor, run the code. Then when you undo, the text changes inside the editor gets the undo steps first instead of the changes in the scene (or 3d viewport) caused by the script in the text editor,even when the undo is fired inside the 3d viewport. This gets super confusing to be honest.