Good day Zir,
It would've been helpful if your article had your e-mail in the end of it or a reply form - I've stumbled upon your article some time ago, but didn't find a quick way to share my feedback and got distracted by something else, maybe the others did too...
1) Thanks for describing CH341A, as it is a simple, reliable and affordable flashrom-supported SPI programmer. However, there's a problem that some CH341A give 5V voltage instead of 3.3V - although, as the time passes, these incorrect CH341A models will disappear, it could be worth mentioning this problem so that your reader will test the voltage of his CH341A before using it. By the way, even the "incorrect ones" may be fixed by a small hardware mod.
2) I didn't like your opinion of SeaBIOS, that it's just "mostly used to support legacy OSes and PCIe Cards with Option ROMs that have only a BIOS compatible Device Firmware." Perhaps this statement has been affected by your personal Tianocore-mostly experience - however, if you'd look at the board_status reports contributed by our community, ~90% of them have SeaBIOS as payload, and judging by the mailing list threads I find these stats pretty close to reality. SeaBIOS popularity is well justified by its' simplicity: less than 50k lines of good readable code, weights a few KB and "just works". Tianocore is quite bloated in comparison and seems to be more difficult to configure and get it working properly. Maybe that's why SeaBIOS is still a default coreboot payload - and really, there's nothing Tianocore can do that SeaBIOS theoretically couldn't. I've been using&developing coreboot for a few years and haven't found any good enough reason to switch from SeaBIOS to Tianocore. You may argue that UEFI is much more popular nowadays, however it's only because the newer PCs had UEFI preinstalled; nobody asked the people if they want UEFI or not, this choice has been kinda forced upon them. Also, I haven't encountered any UEFI-only OS yet; if such an OS would be created one day - maybe just for the purpose of being the first UEFI-only "modern OS" - well that's an intentional reduction of potential userbase for no valid technical reasons.
3) It a bit puzzles me why you didn't mention any interesting floppy-based OS like Kolibri in the "floppy part". Windows 3.1 may seem interesting, however there wouldn't be any updates or software for it, it's stuck at whatever level has been reached during its' lifetime, while a lot of the other floppy OS projects - i.e. some of those I'm offering with csb_patcher.sh script (KolibriOS, FreeDOS, MichalOS, Snowdrop, Fiwix, Memtest, Tatos, Plop, FloppyBird) - are still being developed. At least you've mentioned a FreeDOS, but there are many interesting floppy projects - including those with a minimalistic Linux environment, and PicoBSD - which haven't been mentioned even in brief. Perhaps that's because your Tianocore payload does not support the floppies, so you didn't have a chance to explore this wonderful world personally. I really feel this part is a bit short and could be really expanded. In example, if KolibriOS supports your Ethernet controller, you could access the Internet right from your BIOS and IRCC chat with your friends.
4) By attempting to stay further from "anti-spy crowd", it seems like the information security advantage of coreboot has been almost skipped - i.e. Ctrl+F by Computrace gives no results. Maybe it's not a big loss, considering this security part is well covered at the other articles - however, it may be worth considering expanding this part if you'd like your article to be truly wholesome.
5) Try to shrink your "wall of text" while preserving as much information as possible. Aside from the issues above, your article really seems great and well-written, but it takes some hard work to get through it instead of TLDR hops between the interesting parts. If you could succeed in compressing, will be much easier to read.
That's just my personal opinion, thank you for a good read and I wish you the best in your adventures.
Best regards, Mike