Seems like a proper update to me - that's a great overview there, Jeff.

Although it's an interesting problem in general - removing core features from WordPress. We keep adding things like Emoji or Press This (or enhance them while in Core) and remove other small bits like the media library options or the Title link here. We have long and dramatic discussions over things such as Post Formats UI.

Some discussions are oriented toward "WordPress as a framework" that does not include all of the unnecessary things in core for a lot of projects, other claim that WordPress can't survive without Jetpack (so why don't integrate it in Core, right). And the stats for the Advanced Image Styles plugin that you linked above are also good to note - 20K+ active installs is not a small number, since I'm fairly certain that a good number of the users is struggling since they don't know that this plugin exists, or they have implemented something custom, or another plugin, or the theme provides some styles and so on. The actual number of people with that problem certainly much higher, so I'm curious what does the decision making process look like in that case (or, as with the Post Formats UI in 3.6).

Maybe it's also time to resurrect https://wordpress.org/ideas/ and make some community effort when it comes to "what's needed in WordPress according to the general public" :)