The basic problem with Benefits reform is that life is too complicated. So the system has to be too, to try and reflect this. But people don't like complexity, and they try to force the system to be simpler (hence Universal Credit, which is really just a reversion to the old Supplementary Benefit of the 1980s). But then it turns out that this "simpler" system is unfair because it doesn't reflect the necessary diversity, so you have to break things up again... and then 20 years later there's so much red tape, so people try to simplify it again...
Most of the complexity has emerged because, in a sense, it had to. All changes to reverse that are doomed to fail from the outset, because they miss that vital point. On the face of it, the same will be true of the proposal above.