Thank you for the feedback. I think I will remove the voting system for now while I figure out of solution. I will probably not be adding the user reputation system, unless I figure out a way to do it without facing the problems you have mentioned. As for collaboration, I will add a feature allowing app maintainers to set whether or not non-maintainers can add scripts without maintainer permission. Thank you again for the feedback, it was very useful!
I have, but I think it would be a bit too expensive on my VPS, but might use it if my site ever catches on. I have also considered using something like Try, but it isn’t a full sandbox.