Keith, that would be fantastic.
I still want to pose the question: what future use cases are the characters being reserved against? We're proposing what is arguably the smallest meaningful subset of URI's, which is already a highly restricted (although widely accepted) grammar for hierarchical resource identification. To Chris's point, this is not utilizing characters that are commonly used for other purposes, or even characters that are part of the URI syntax but less commonly used. This is a bare minimum for hierarchical expressivity.
Accumulo has been through quite a few major revisions and (as far as I know) the only changes to this component that have ever been implemented involve adding characters to the grammar to make label structure more expressive.
I just want to suggest that its better to focus on problems that people have today rather than ones people might have tomorrow.