What we need is a quick way to toggle features -- maybe we don't even HAVE to, like:
automatic personal hotspot shut off when you have wifi on your iPhone and on your mac (it detects that both devices are on the same network so the iPhone doesn't bother sharing via wifi with the mac when the mac already has it!)
automatic 4G when driving (iPhone detects accelerated movement and will not try to connect to wifi hotspots along the way).
And if you're on a train with Wifi?
----------
Dammit. How the hell am I supposed to sleep tonight?
Perhaps by getting out more?