Internal tensions
In an expository hypertext, merely indicating that certain nodes should be visited is not enough to assure that the reader comes to the nodes with the proper background understanding of their location in the overall argument.
As with any hypertext there is a tension between the overall network and the temporal sequence of reading.
Literary hypertexts play with this tension.
It seems to me that expository hypertexts can do so as well, by being less obsessive about revealing overall structure, and using link patterns to have that structure emerge slowly in the reader's mind.