watchOS 3 was a huge, almost paradigm-shifting update. Two huge updates in a row is asking a lot.
I'm interested in what the HIIT workout will be; if it can be customized, etc. But not interested enough to install iOS 11 beta and the watch beta.
The rest of the update isn't all that exciting to me, but I'm fairly happy with the watch as is. I'll try the Siri watch face I'm sure, but I'm not expecting it will help me a lot. I don't care all that much for fancy activity animations. But I guess "you're only a 12 minute walk away from completing the move ring" is a good idea. I'll have to see what the flashlight for a pre-dawn or nighttime run looks like, but I wear a head light for those now anyway, which I'm sure is more effective for visibility.
The one thing I'd really like to see now is to have the watch light up with every received notification. There are times when I get one that I can't tap the screen or raise my wrist the proper way in time to see the notification. If the watch receives one, I want the display to turn on (so long as theater mode is off, of course.)