Scrivener would be a better choice, if you are looking for something more like Index Card on the Mac. In fact Index Card was inspired by Scrivener’s corkboard interface to begin with. It has two main text editors attached to every card, not including the title and synospis, both easily accessible and easily hidden on demand.
Scapple is intentionally flat, and has a design that at every point is opposed to the concept of hiding data within data. It instead encourages us to spread our information outward on a two-dimensional plane so that they are not only visible, but always continue to use the bulk that is required to construct them, never allowing their information structure to be subordinated or obscured by others around them. This is very much on purpose, and I would say that reneging on that would in part dilute the overall concept and cause it to drift back into the already well trod realms of diagramming software; realms that Scapple was made as an opposing answer to.
The trick supplied above strikes me as a good compromise. For one a hyperlink does not conflict with what I have described, in that it can be used to route one to external information. However it can be used to create a more dimensional data structure (I hesitate to use complex vs. simple in this description, as a flat data model can be quite complex, it just doesn’t try to say all of the complexity out loud with UI straps and bolts and features).