I used to work on a Mozilla Webmaker project for "remixable web games", so, similar to Scratch. Your first point that more polished projects would be less remix

I used to work on a Mozilla Webmaker project for "remixable web games", so, similar to Scratch. Your first point that more polished projects would be less remixable is spot-on, and the primary reason we stopped working on the project. The more polished we made a game, the less there was left for anyone to add onto it. Meanwhile, our low-fidelity game prototypes had far more user activity. We wanted to make high-quality & highly-remixable games, but we never suspected those goals would conflict with each other so much.