The Sandbox has undergone some evolution over time. After the first one accumulated over 200 answers (mostly deleted), we rebooted it earlier this year. We also discussed time limits, so that abandoned answers wouldn't live forever and make it harder to notice the new ones. And then, recently, we ran into the auto-protection problem -- the sandbox keeps getting protected by the system, blocking low-rep users from answering.
In an answer on that last post I reported some feedback from Shog9, including what some other sites have done to solve their sandbox problems. Comments there have raised issues with an approach that initially sounded promising. We could ask the other site how they dealt with those issues, but -- maybe it's time we gathered some requirements so we know what we need before we try to solve the current problem.
I'll list here some requirements that I believe are obvious and uncontroversial. (If you disagree, let me know in a comment.) Please use answers to add requirements, so the community can show (through voting) which ones have support. Feel free to propose requirements that we aren't currently satisfying but you think we should.
Base functional requirements:
Anybody, including new users, can use the sandbox to post draft questions for review. (Current: there is one sandbox question, and drafts are answers. Requires 5 rep; we could lower it.)
Anybody in the community can provide feedback on sandbox questions. (Current: feedback is mainly in the form of comments, and sometimes edits.)
Community members can easily see current sandbox questions without digging through obsolete questions. (Current: we delete inactive or completed answers, which sort to the bottom in the default view.)
Community members can easily tell whether a sandbox question is active or obsolete. (Answers that are not deleted are active.)
We also maintain an answer with links to graduated questions, but I'm not sure what the goal (or underlying requirement) is. If that's important, somebody please describe the requirement in an answer.
For those not experienced with writing requirements: focus on the outcome, not the implementation. I've included notes in parentheses about our current implementation, but details such as using comments or deleting obsolete answers aren't the requirements -- if we came up with another sandbox scheme that achieved the goal in a different way, that would be ok.