Now that Arcade has been unleashed, I was thinking that what if the Steam Workshop had a feature where you can upload your own video game as a custom arcade attraction (Using HTML5) that has a chance to be showcased in the Warpzone Arcade?
Make a Combat Game… or a Platformer Highscore game… A Flappy Bird Clone perhaps?
Reason why I am mentioning this idea is that certain game engines, whether it may be Unity, Unreal, Godot, Gamemaker, etc, has the option to export the game as an HTML5 and that they can be played online, it could take advantage of using Steam Workshop, just like where users upload custom models there.
Also, if you think about it. Where there is a DIY-Store at the Plaza, why not buy a DIY Arcade cabinet of different varieties (Classic Arcade Cabinet, Cocktail Table Cabinet, Countertop Cabinet, Seating Cabinet, etc…) So then you can deck out your Condos with plenty of custom Arcades, loaded with either your own Custom HTML5 Arcade game or somebody else’s. Make your own Arcade Center. Heck, If you happen to have either the Theater Condo, put some at the Theater lobby. Or The Resort Condo… You know where the arcade cabinets used to be. 
What do you think? Can’t hope or beg that this idea would get through but figure I write something about it.