I've managed to fix the problem on my watch, so far so good. Instead of uninstalling the Message+ app on the watch. I went into my Andriod Wear app opened up Settings and went to Block App Notifications, your Message+ should be there. Once you have unblocked Message+ you will start getting the notification again, but only with phone numbers. You can fix this as well, once it has been unblocked from your Android Wear go back to your watch, go to your apps, find the Message+ and click on it. The app will then prompt you to allow it access to your messages, phone calls, and contact list. Once you agree to this it will now send you notifications again, with the names showing.
I don't know if this works for any others, but it seemed to fix my problem.