Today, I first noticed (in the Office 365 Admin Portal) that a new option was added :
Apparently, you CAN disabled DirSync. Although there has been no (official) statement from Microsoft that it is possible, Microsoft always said that it would become available at some point.
Wondering what would happen if I clicked the link, I was taken to another page where a bit more information was displayed:
Although I didn’t go through disabling DirSync, I mailed Microsoft to get more information on this.
Of course, I will keep you posted as soon as I get more information.