Standardize it. Policy makers should provide a standard message, or small set of messages websites can reuse and consumers recognize with links to an EU-run informational website easy to understand for consumers. I don't understand why it wasn't implemented this way, maybe to allow for more freedom of implementation, but we have seen that has hurt the policy effort. Just standardize it.
Incidentally, with all of the Organic / GMO-Free / et all certifiers out there, would a privacy badge be the way to go, or is that backwards thinking in the way of early internet site badges?