With Bernie talking of wanting to handicap Mercedes, I was having a think about if there could be a potential long term solution to the problem without being subject to political interference.
I came up with an idea - at some point (or points) during the year, teams have to make all (or a certain percentage of) their designs open and transparent, or let their cars be open to scrutiny from other teams. Even if it's just at the end of the season.
But in theory I see two advantages - teams won't have a locked in advantage for too long, and teams probably won't be so inclined to spend huge sums of money on small things that ultimately won't give them a long term benefit.
Of course, the policing of this policy is where the issues, no doubt, would arise... could you trust the teams to submit accurate designs to the FIA? And you'd be in danger of suddenly having a host of identikit cars on the grid.