Native file dialog for Blender

Native file dialog add-on for Blender. It uses Tkinter as the default window system.

From this:

... to this:

How to install

macOS

1. Be sure that Tcl/Tk are already installed in the system. Commonly they are named as Tk.framework and Tcl.framework and placed in /Library/Frameworks/ folder. If there are no such files, follow the next step. Otherwise, read step 3.
2. Firstly you need to install Tcl/Tk frameworks for your system. The best choice is ActiveTcl. You can find it here: https://www.python.org/download/mac/tcltk/.
3. After installation download one of the add-on's releases and place the folder in blender.app/Contents/Resources/<version>/scripts/addons (blender.app directory can be opened by mouse right button clicking on "Show Package Contents").
4. Run Blender. Click File -> User Preferences.. -> Add-ons -> System. Make System: Native File Dialog active.
5. Now native file dialog system are working. There will be the system dialogs instead of standard ones (the screenshots above shows the macOS example).

Disclaimer

There may be errors in the process of work. Add-on overloads already built-in Python scripts. It's absolutely impossible to rewrite everything without rebuilding the whole editor.