Mainly, Core needs to replace its PoW function, preferably to a function which make any effort to create ASIC for it economically nonviable.
Guy is pushing for a change of PoW algorithms to be essentially GPU-only (that dynamically change every ~12K blocks as well as a phase-in and phase-out from previous and next functions on each end) in case the hard-fork of Classic takes place. This would prevent any kind of ASIC development from taking place on Core chain, and act as a defense against 51% attacks from the Classic chain. The real solution is to simply not allow Classic to take place.
Nothing about PoS that I read in that post anyways.
Ask yourself this, why would Guy Corem be pushing for a defensive GPU-only PoW system that would essentially end the hardware development by his company, unless he truly believed it was necessary for Bitcoin's survival? I sincerely do not believe it to be out of spite.