Why would they release a crappy version of some core functionality? Well, here's what the article says:
Apple wants to use a common foundation for both iOS and macOS. However, it was released way too early, and for the first time (at least in my experience) Apple deprecated several features without caring about compatibility. And to make things worse, lots of former features are now broken or not implemented at all, meaning that we had to add lots of workarounds or implement stuff on our own. And there’s still work left to be done.
10.12.2 introduces new issues (it seems that Apple wants to fix at least the broken compatibility now) and of course fixed almost none of the other issues.Once upon a time, desktop Macs and functionality like the PDF engine in Mac OS were important to Apple. While it may seem like minor functionality, the core graphic rendering engine is more than just a free tool for casual users, it's yet another essential component for the professional user class.
The writing is on the wall. The Mac platform is dying and Apple can't shovel dirt on it fast enough.