A world in which all laws and contracts were required to be written in Lojban would be interesting.

That looks hard. More politically feasible might be a language I've unfortunately forgotten the name of, ordinary English but with some extra rules designed to eliminate ambiguity -- every noun has to carry a specifier like "some" or "all" or "the" or "a", etc.

Legalese might be similar to code, and there is lots of interest in making law machine readable. So don't give up; check back later.