AnimationRootNode : Add an 'Input' node for use in nested Root nodes

[toafloast]

I think it would be quite nice if an 'Input' node existed, for use in nested AnimationRootNodes. It would allow the user to tidy up and compactify their tree, and it would also enable the user to swap out sections of nodes by putting them in a AnimationNodeBlendTree.
Here is an example where this would be useful.

The Yellow section dictates behavior of the Weapons- now, I could configure the Filters for each weapon- twohanded or onehanded, tilt the body or not, etc. But, what if instead I could put that in a BlendTree?

Great, I've put it all in a BlendTree- I should be able to easily swap out all of those settings through code, and keeping that BlendTree stored inside of the weapon somewhere. But wait- there's an issue- I can't connect anything to it. The blending won't work properly!

Thats where this Input Node would come in handy. It would allow you to connect into the Node, and any advanced animation behavior can be handled in a nice, simple package.
I'm still new to using the AnimationTree myself, so I don't know how difficult this would be to implement- nor, if this is really an issue and I'm just doin things in a weird way. But I thought it through, and I'd definitely love if something like this could be added.