Do all 72 parts of the Storyform have to be in there to effectively make an argument?
Theme encoding involves three acts; in each the main thesis vs. antithesis is presented within a sub-thesis/antithesis. The sub-thesis/antithesis can be argued six different ways--that's eighteen arguments. Multiply that by the four through lines for an astounding 72 arguments. I'm overwhelmed!
Am I missing something here?
What Dramatica theory is doing then is forcing me as an author to develop extensive arguments for and against the main thesis/antithesis, with three main sub-thesis/antithesis areas to explore in four different contexts. Do I have this right?
I wasn't thinking of writing a 400 page novel here! 
Is there any way to simplify at all? Do ALL of the 72 arguments need to be there? (Again, what if I leave out one throughline?)
Your question concerns the quantity of information that can be necessary to completely explore the thematic arguments in a story. You ask, do all 72 arguments (interactions) need to be there? The answer is, yes and no. To completely argue the thematic issue, all of its relevant positions need to be made. HOWEVER, the depth to which this is done is COMPLETELY at your discretion. For example, you can illustrate Self Interest v. Morality in a single sentence or observation: "I slave day in and day out for our family, never taking any time for myself, and all you think about is getting more money so that you have a nose job!" That simple example (I have no idea where it came from) could easily act as the exploration of one of the 72 thematic issues. If you're an adept and clever writer, you can be far more original and succinct in your own examples.
Whatever you do, at least address the thematic conflicts in each of the four throughlines. Otherwise an entire aspect of your story will be noticeably absent.
