Definetly changing into 4 weeks power down period will cause short term extreme selling pressure. All those that are powering down right now (because they want to get rid of steem and are done with this blockchain) - all those users will power down almost instantly. And dump all that liquid steem on the market.
Indeed, almost for the first time we are able to agree on one thing. I am happy about that, especially about the fact that you have further made solid points on why the 13 weeks power down should remain. If the 4 weeks is implemented I will power down 50% or more of my account and be waiting for the sell whistle. Hahahaha. Thanks for your time.