mmmmm... the lobbyst establishment would push for loopholes,benefits etc. The best way to prevent this is to create a sacred tax code thats fair for all, so no one dares to mess around with it.
That doesn't exist and never will. No piece of legislation is 'sacred'. We can tinker with the code all we want, but it is still just that .. the code. Even if we simplify it, down the road special interests will bloat it again.