I don't think there's much of a problem with actually reasoning about a law's text that a computer can help solve. The complicated bit is weighing equities, which still requires humans and lawyers.
Absolutely. Although the clarity by creating algorithms from tax tables can be helpful, and sometimes the wording seems ambiguous. Although you probably also need lots and lots of examples. (It is as if you need unit tests!)
Most tax-related rules in the US are specified in an XML-based business rules language. That's partly how tax prep companies are able to get rules that don't finalize until 12/31 into products that have to ship 6 weeks later.
+1. I see one benefit of this language -- it could make it much easier to write programs to compute taxes and benefits. Beyond that I don't see what it could possibly offer.
Are there any lawmakers, lawyers or judges excited about this, or is it only programmers?
