This change is intentional, and fixes a problem with the current implementation of shared folders. For compatibility with guest OSes which have no idea what a symlink is it is at the moment interpreted on the host side, and this means one get unexpected behavior with guest OSes which know what a symlink is (e.g. if a symlink on a shared folder mounted at /foo would point to /bar/file it's impossible to do the right thing on the host side).
It's of course fixable, but far from trivial as the separation of symlink processing between guest OS side and host side needs to be redesigned. This can't be done quickly, so the only option was to disable symlink creation. Too many users/applications were caught by surprise by the non-standard behavior.