You can sett allowed types on the content area in the model as well. That will make it not possible to drop "wrong" contenttypes into the area. You can also use a class that inheritsIViewTemplateModelRegistrator instead of controllers.

Have a look in the demo package from episerver, alloy templates mvc. They use this. You can read more at, http://world.episerver.com/documentation/Items/Developers-Guide/Episerver-CMS/9/Rendering/Rendering/

This isn't about setting allowed types. I wasn't clear on that, and I apologize. This is about handling the PageData in the ContentArea and the BlockData. For an example, consider a navigation section where it could be an internal page link, or an outside, custom link. For the internal page link, I want to allow a page to be dropped in, and for outside, there are a couple options defined as Blocks that inherit INnavItem. 

My AllowedTypes and property would be defined like:

[AllowedTypes(typeof(INavItem),typeof(PageData))]
public virtual ContentArea ThisNavigation {get;set;}

Now, when I do

@Html.PropertyFor(m=> m.ThisNavigation);

It will render the blocks according to their controller or matching view. For the page, you can specify a PartialContentController. Or am I wrong here? If I am right, how do I make that PartialContentController only apply to items in this list? For instance, PageData in this list I want to render differently than it would dragged into any other ContentArea. I might have a "Callout" ContentArea somewhere that allows only PageData and in that list the Page will render with an Image and Teaser wrappedin a Link to the page like a typical callout. 

Hopefully that helps clarify the state my mind is at right now with playing with these ideas. I'm sure I'm missing a concept or approach.

At any rate, thanks for replying and helping.

I wrote a blog post a few years ago where I do something similar. It might be just what you need:

http://world.episerver.com/blogs/Per-Magne-Skuseth/Dates/2013/8/Developing-a-drag-and-droppable-menu-MVC/

As Per Magne Skuseth does in his blog post, adding a Tag is the way to go for this.

You keep your default page controller as is and setup your new one to a specific tag that you supply when you render with PropertyFor.

For the rendering with the tag the pagedata will be routed to your new controller and everywhere else it will be routed to your default controller.

Thanks Per and Erik for pointing that out. I was missing the tag on the partial controller. I basically created the same solution before running into the issue and searching, so I wish I would have posted sooner. It would have saved me a bit of time. But, on the flip side, it lets me know I am not far off base with my line of thinking if Per has done this in the past and it was a good idea then. :) Makes me feel a little better.

Adding the tag to the template descriptor made everything click into place and work as I need it. The blocks I already had rendering as needed so this zipped up the solution nicely.

Again, thanks for both of you pointing out that missing piece, and supplying the blog link to the solution.