It's very easy to entitle something a "modest proposal" but that doesn't make it a modest proposal. This particular proposal is outrageous inasmuch as all the PU manufacturers invested an absolutely enormous amount of time and money and resources on the basis that the PU, partcularly the fuel efficiency of the ICE and also the effectiveness of the ERS, was supposed to be a key performance differentiator. If Ferrari had done the best job I would be completely opposed to any proposal that would rob Ferrari of that hard won advantage and so it would be rank hypocrisy of me to be anything other than implacably opposed to pegging back Mercedes and penalising them for doing a good job.
Last time we had an engine development freeze we ended up stuck with prehistoric engines for about 7 or 8 years longer than we should have been. Everyone moaned about the cost of having to design and build the new PUs. Their introduction had to be postponed. If F1 were to immediately peg back Mercedes now and go back to performance parity, these PUs will not be developed (or only developed for reliability), they will become old hat and F1 will find itself unable to convince any but the most gullible of manufacturers to invest in new PU technology again. Why bother if you're going to get penalised for winning?