John Gruber, on the fact that the WiFi and Bluetooth buttons in Control Center no longer act as on/off switches:
This is an interesting feature, but I think it’s going to confuse and anger a lot of people. Until iOS 11, the Wi-Fi and Bluetooth toggles in Control Center worked the way it looked like they worked: they were on/off switches. Now, in iOS 11, they still look like on/off switches, but they act as disconnect switches.
Off the top of my head, I would suggest making them three-way switches: on and connected, on but disconnected, and off.