The timing of this (vs. the Google/Samsung arrangement) really makes it look like Google's involvement with Motorola was simply to intimidate Samsung. The message was we'll piss away our advertising revenue to destroy you if you don't do what we want. Short term success maybe but in the long term it puts Google firmly on the Microsoft track. You can only gain so much via intimidation.
Alternate theory: this is samsung throwing their weight around. Google purchased Moto because they wanted to get into the devices business, Samsung tells google to get rid of it or else they will continue to diverge their ~70% of the android market away from google's version of android.
Google clearly wants to be a hardware manufacturer: they've been circling the market for a while now, trying different things: they bought moto, they bought nest, they keep doing nexus devices, glass, the ever-growing lineup of google play editions, chromebooks... I don't think they bought moto just to be a bully, or just for the patents.
