I'm having a similar issue as the OP; I rarely receive text notifications on my watch. I got my watch yesterday and since pairing it with my HTC Desire I've only been able to receive texts on my watch a handful of times. This seems to be random, not related to any particular contact or text app. I've tried the default Messaging app, Google Hangouts, and Go SMS Pro and neither have been able to give me consistent text message notifications on my Moto360. When I receive an incoming text it simply notifies me on the phone as it always does. The watch screen stays black, no vibration, when I wake the screen there is no notification.
Furthermore, the few times I have been able to receive a push notification for a text message, I have no option to reply on the watch. It clearly states on Google's help page that I should have the option to voice dictate a reply using both Hangouts or the default SMS app.
I've tried restarting the phone, restarting the watch, resyncing the app list in the app, and even resetting the watch. So far, nothing has done the trick. I'm not on mute and I'm not in theater mode. Does anyone know what gives? Could it be my phone?
Other notifications seem to display fine, such as how many steps I've taken and the heart monitor.