It's very suspicious that Motorola was not there at MWC. Even if they just launched some RAZR devices, surely they have a few more upcoming devices that will launch in the next few months. So why weren't they at MWC to present them?
Because Google is in the process of completing the acquisition, and because they've just replaced the head of Motorola, they need to go through a period of transition, and see what projects continue and which get axed. It's possible that Google didn't like many of the products that were supposed to be shown at MWC for example, and they want a more unifying strategy for Motorola going forward.
Another reason is that Google is preparing something special with Motorola. They must've been working for months on some devices already, and they want them to be a surprise to the world at the time of launch. Of course Google has said that they will put a firewall between them and Motorola, but even if Andy Rubin has little knowledge of what's going on with Motorola, he can still interact with Product Managers and developers from Motorola, just like he can with the ones from Samsung, HTC, and so on.
Plus, their bosses, Larry Page and Sergei Brin, would still know everything that is going on with both the Android team and the Motorola team, and they can still coordinate the teams at a very high-level, even if both teams are mostly autonomous. I understand Google's need not just to let Motorola run as an independent business, which I think is always a smart choice, because mergers usually kill the acquired company, unless it's left alone, but also because they need to not make their other partners angry, which is why I don't think they will give Motorola special treatment, but they will apply their own hardware strategy to Motorola.
What this means is that Motorola will get nothing that Samsung or HTC are not able to get too from Android, but Google will give the Motorola division, the vision for how to compete in the market. For example, something they could, and I hope they do it, is to make Motorola devices run only stock Android. That would make a lot of sense, and their partners have no reason to complain anyway. They could always do the same. Of course they don't want to, because they want to use their own skins. But this is an example of how Google could still run Motorola in their own vision, without making their partners think they are giving special treatment to Motorola.