I spent some time cleaning up the Sandbox today. It's getting to be a slow honker to load. This is especially true when I'm linking in through a comment notification.
I spent time removing the body contents of deleted posts and flagged a bunch of the longer comment chains for deletion (must be done by a moderator), but the truth is, the current Sandbox is becoming systemically unwieldy.
However, as the site ages, it's also true that it will (if it hasn't already) become a bit messy to find the "current" sandbox.
Proposal #1: I propose that we have an official "Sandbox landing site" that is the single Meta question we refer all people to. Along with the instructions for the sandbox, it contains a linked list of all previous sandboxes and the currently active sandbox. Ideally, this post would be answer-locked such that no answers can be posted. Users must move from this "landing site" post to the "current" sandbox page. All older sandbox pages would have their question body text deleted and replaced with a link to the landing site. (e.g., "Current active sandbox may be found here")
Proposal #2: Perhaps a simpler alternative is to rename the old sandbox pages (e.g., Sandbox for Proposed Questions 2014-2017) to specifically indicate they are inactive (e.g., "Inactive Sandbox 2014-2017") and specifically label the current sandbox "(Active)" This is basically a proposal to continue what we're doing with an improvement in searchability. (When I search for "Sandbox for Proposed Questions is:question" one and only one item should come up.)
The two proposals have pros and cons. I consider #1 to be cleaner and easier to use. It allows community promotion ads, the Help Center, and other convenient redirects to use a single URL that will never change.
On the other hand, #2 is simpler in the short-term and more reflective of how we've used the service in the past. It's just inefficient because we're forced to update all the links whenever we start a new page. If we avoid starting a new page to avoid updating links — the page becomes systemically ugly (which it's becoming now).
I believe the actual maintenance burden would be more-or-less identical. I prefer proposal #1.