I hate to be so bothersome, but I had hoped to have at least the achievement system able to work along with the gamepad.
But I've tested on two different projects: Whenever I include the Steamworks addon, the trick with altering the package.json file does not work in fixing the controller.
Only when I delete the Steamworks addon from the projects, entirely, I can recreate the controller functionality.
I don't think it is appropriate with making a new github bug report, because I understand that it is the webview team that is dragging their feet on this one.
But just wanted to clarify, that I've tried with the Steamworks enable overlay - both on and off, with app ID 480. With debug mode enabled the gamepad doesn't work, and with it off- the game won't even start. I'm using the SteamWorks 1.5.0.0 version.
Seems like it is no steam plugin if you want to have controllers.
My personal solution is just to wait with integrating the Steamworks plugin until the end of production, but it seems a little risky - knowing how much those pesky steam players loves their steam features. :)
Well, maybe this wall of text could be informative and useful for someone.
Happy holidays.