Why not more types of "add-able" components?

Hey guys,

I was wondering why you only can have Actor and SceneComponents as Blueprint Script Components? Was there a reason for not having more types of components like collision components, primitiv components and so on? Imagine you have a just primitve component with a bit of script that you can add to any asset in the level. You could create a plug and play interaction system and so on. Add a whole new level of modularity.

So was there a reason for it or is it something that might come later?