Unlocked for all: I look at The Making of Karateka, which I loved, but with some thoughts on how you curate a project like this: https://everygame.tumblr.com/post/732162143400640512/the-making-of-karateka-nintendo
I think the factors that made Karateka such an obvious choice to launch an initiative like this are also going to make it a difficult proposition for some: Jordan Mechner's been diligently chronicling and writing their own career history online for the past twenty-something years, so from a production standpoint, you can approach it without having to worry that you're going to have to scrape for supplemental/documentary material, and you can spec out a lot of that work far ahead of any of the technical work... but the obvious flipside is that the carcass of Karateka has long been picked clean and you've really got to stretch to find something new to bring to it, and for a game as slight as Karateka, there probably aren't many people out there who both know enough about the game to automatically register a release like this and also haven't already made their mind up about the game, or still have an appetite for whatever tidbits are left to be told.
(another important part of the equation is that Karateka's the kind of IP they can license with relatively little hassle, without having to worry about rights holders stifling their project or byzantine legal issues forcing them to talk around any of the truths surrounding a given game)
re: the relative lack of contextual comparisons to other games: I would presume that there's still a lot of paranoia around directly citing other games for fear of being bulldozed by other IP owners, irrespective of the terms of fair use, and that their current solution to that problem is to simply avoid doing it wherever possible. I'd guess the abundance of talking-head commentary ties into that as well—it's simple, it's malleable, it makes for good marketing footage and there are always a ton of people up to contribute, hence why there's always so much of it.