I like this update. I hardly ever used that side button for contacts. This app drawer concept makes a lot more sense. It seems to work well, but some existing third party apps need to be updated to support it, I think?
WARNING: If you work a lot with your Apple Watch on, especially if you wear gloves, turn off the 911 S.O.S. feature, or at least set it to swipe to confirm you want to call. I changed mine right away because I was worried about accidentally setting it off (especially since I have a toddler), and when I was framing a wall the other night wearing my leather work gloves, it set off the S.O.S. 6-7 times from accidental "holding" of the side button. Like I said, I was lucky I had turned on the "swipe to confirm" functionality or the police would have made an unpleasant visit.