I recently suggested to a new user to post his question (16980) on the sandbox as it had some issues and I thought he could benefit and narrow down the question to something that wouldn't be closed as off topic. He responded he tried to do that but needs 5 reputation in order to post to meta. I presume the requirement is there to mainly stop spammers in meta but aren't we barring the sandbox from people who most need it?
The reason, why one needs 5 reputation to participate in meta is written in the help center:
Because we allow anonymous participation, we require a small bit of parent site reputation to prevent spam, and ensure that meta is for active, engaged members of the community.
This was never a problem. But now we have our own sandbox in the meta, and I agree that we should allow 1-rep-users to post their question draft into the sandbox. After all, the sandbox is made for users who are not yet fully accustomed to the rules of this stack.
I don't think the amount of spam in meta will drastically rise if we lower the meta privilege to 1 rep. The Programming Puzzles & Code Golf stack for example has this (for the same reason), and they don't have spam problems.
Therefore I say:
Reduce the needed reputation for the meta participation privilege to 1 for this stack