I think most laws started out simple. Reality isn't simple, however. And I would bet that any attempt to simplify it will be adjusted over time and will end up being just as complicated again.
I mean, the law could be simple in the sense that it basically says "don't to stupid shit". But then it just becomes more subjective which in the end will be even less fair.
All the complexity in the law comes from the attempts to make it as fair and objective as possible.