The slice deck already looks like someone was presenting to non-technical management - why would they have put highly technical details in there too?

So then it's all about the quality of the advisors they have access to, but given the nature of the materials, I suspect few people have been able to see them.

We just won't know till the whole thing gets released, if ever.

And to the second point, obviously I couldn't know for sure, not having seen it, but it's very very common with these types of presentations within government agencies and defense contractors to have 5-10 overview slides, the conclusion, and then behind that 20 reference slides that are more of an information dump. The idea is that the first set of slides is enough for most people, but if you want to dig deeper, there's additional detail.

Greenwald presumably has plenty of access to technical advisors at the Guardian and elsewhere who can help sift through.

You simply can't build the system that does what Greenwald claims for $20 million. You can build a drop box + FISA API for that amount though, but that would mean Greenwald is incorrect (or lying, take your pick) and the companies + NSA were telling the truth about that aspect.

But he doesn't, either because he is obstinate or because he doesn't understand the technical nuances.