I think the biggest constraint holding them back from giving local control is the fact that the hub works with so many different radios.
The can't add Honeywell support directly to the hub. They can add a radio to control it, but the commands need to come from Honeywell, thus pass through the Wink servers.
Same for Nest. Same for GE. I guess they just figured that if so much stuff HAS TO go through the cloud, might as well just make everything go through the cloud.
Even if they did localize some of the control it STILL has to go through the cloud most of the time since I doubt the average user has any form of static DNS entry going to their house.
Insteon's Hub app allows for a local AND remote url. that way, the control is local when on the same network, and through their cloud when somewhere else. But the problem with that is they use their own devices on their hub. Wink uses other company's devices on the Wink hub, and most require some form of translation.