Putting it alongside MeeGo would defeat the purpose of creating MeeGo. Attrition would push users towards the familiar platform, and away from the new one.
The problem is that right now only Google is in a position to decide the course for Android as a platform.
Even if they are not going anywhere any time soon, this lets Google dictate where the platform goes.
At least with MeeGo it's tied up with so many involved parties that no one player can determine the course of the whole thing, which I think is Nokia's goal with this.
They gain the benefits of pushing even more of the core development outside like with Android, without being under the Google umbrella.
It just occurred to me. Nokia doesn't want to use Android for the same reason no one else wanted to use Maemo.