How to simplify the PAYE system (or not!)

I'm told that an official from HMRC, who wishes to remain anonymous, has identified two key changes that would simplify our PAYE system and avoid most problems:

1. Stop anyone from having more than one job at a time; and
2. Only allow people to change jobs at midnight on 5 April each year.

No - I don't think they were serious.

Do you have any other ideas in a similar vein?