I'd avoid premature extraction at all costs, a little duplication in the end can be much easier to deal with.
If you keep in mind that most of the complicated model stuff should be dealt by the model and not the controller you'll probably have a very slim controller in which case the duplication will be minimal.
You can always share the views if they are too big or change too often, but since they're essentially two different parts of the application I'd just treat them as such.
Just my two cents...
