I would also appreciate the rich functionality of an rsync-like tool for SAFE.
At the same time, I agree with @danda’s perspective of the CLI as a Swiss army tool.
Those design goals are typically in opposition to each other.
I believe what I describe beginning here and further here would allow both with no necessary compromise. In brief, the CLI tool with its default subcommands being broadly functional, and with externally developed subcommands being deeply functional as-needed.