One of the reason someone in the actual 'investor class' doesn't jump into steem is because doing so, requires a long vested period (13 weeks). A 4 week powerdown would make steem more attractive, though still concerning.

Do you want to see the price of Steem plummet to near nothing? Vote for four week power down.

4 or 13 weeks, people who want to get out, already can get out. Shorter time wouldn't have much of an effect on the price from that perspective over even a few months timescale. It may cause a short dip initially though.