Yes, sorry for the inconvenience of this change -- dropbox is supposed to be set up under each user's home directory rather than installed centrally. While this fixes quite a few other complications it does make things more complicated for you. Fortunately there is a pretty good way to get dropbox working the way you want -- using /etc/local.d. See if this works for your needs. Try creating an /etc/local.d/dropbox.start script that will start dropbox as the user of your choice when the system boots:
#!/bin/bash
su username -c "/usr/bin/dropbox start"
Then...
# chmod +x /etc/local.d/dropbox.start
This will run dropbox as user "username" when the system starts.