Just about the only thing I use Dropbox for is the public folder. I've gotten many of my friends and collaborators to sign up for the service, based on the recommendation of this very feature. It's been a real boon for rapidly iterating front end mock ups.
Dropping support for what Dropbox evidently regards as "edge use cases" is not how you "build the next Apple or Google". The Public folder may not be used by the majority, but it is the domain of the geekiest, most hacker-spirited segment of users. Why trample that most creative segment?
The removal of my team's files from Dropbox and searching for a better sharing method begins now.