On Gutenburg being a sentry - I think that's just a mechanical decision. The vast majority of trace to tag ice has been sentries. It's the standard bad thing that NBN sentries do.
On why the Pioneer (or genius, or whatever) cycle has the flavor text, I think the point is to draw attention to the fact that each person was fundamental in the development of that particular Corp. After all Gutenberg -> NBN isn't the clearest connection, until you make the information revolution connection. Ditto Turing.
On Blacklist and Student Loans, both represent the runner's past coming back to haunt them, in different ways. I also like how Blacklist fixes your past in stone, only to be added to, never to be forgotten - which is what a Blacklist does, really.
Student loans also mounts over time - which is a great way to represent the ticking time bomb of debt.
As for it not being applicable to certain runners, I think that's more of a deck construction thing. A Drip econ Andy deck isn't going to be bother much by student loans. However, the two runners hit hardest by it - MaxX and Kate - totally make sense as people who went to school at some point.
As for Kim - hey, vocational schools are a thing, right?