This took me ages to figure out so am just posting in case anyone else is having this problem. After receiving my Apple Watch yesterday I didn't feel like I was getting a tap for all notifications - it made sound - but no tap. It seems that if you have notifications set to mirror your phone (the default) it will base whether or not a notification warrants a tap based on if that notification is set up to make your phone vibrate (which I had turned off). So I set my phone to vibrate for notifications. Now I get the taps fine.