First I'd double check what I said to make sure it is true. (I'm going off of documentation, haven't actually tried it).
I wasn't aware of Tool when we overhauled hbck a while back. From a usability point of view, I'd really prefer it if we "Tool"'ed hbck. (look at copy table, or import/export for examples – it is really simple).
The system properties approach won't work intuitively with the hbase script, and the extra wrapper code will save trouble down the line.