no offense, but your answer is exactly the generic answer i was expecting
No offense, but you won’t mind if I do take offense at that, right?
who would NOT benefit from image categories/tags to help with sorting and finding media?
People who don’t want the extra overhead of yet-another-thing to do during the upload process.
who would NOT benefit from the elimination of invalid gallery styles?
Those who aren’t encountering invalid gallery styles. (It’s probably your theme that’s doing it.)
who would NOT benefit from the addition of ‘0 columns’ in the gallery UI?
Those who just want a simple click-and-go gallery without the extra fuss.
would any of these add any bloat to the code?
Yes, they add extra code, and to the user they add more buttons and options, more things to do.
it is bugs and shortcomings such as these that force users to install sometimes bloated and buggy alternatives that can create headaches for everyone
You mean plugins, the things that generally only do one thing, and usually do it well, and are there so only the people who want that one thing can use it?
and how many people have griped about WP removing p and br tags?
Plenty. WordPress is volunteer developed, it would be great if one of those people stepped up to the plate: https://make.ww.wp.xz.cn/core/handbook/the-wordpress-codebase/
as for broken links, who would gripe about being notified about broken links? a majority, or a (very small) minority?
The majority of hosting providers. Scraping for broken links is very processor-intensive, not recommended on most shared hosting providers, and actually banned on a few.
And, like I already said earlier, plugin: https://ww.wp.xz.cn/plugins/broken-link-checker/
should the guy searching for information on the www be aware [about no tags on pages]
If you actually have those words in your content, like any one focussing on SEO would, the “guy searching for information” will never notice. The search engines don’t care about tags, they care about content.
And, like I already said earlier, plugin: https://ww.wp.xz.cn/plugins/add-category-to-pages/
disable thumbnail gen – that’s your answer to re-working an obvious disk space wasting problem?
No, that was my answer to “for some reason it’s apparently a much better idea to generate a pile of thumbnails that may never be used” meaning you can disable it and then generate your own thumbnails in your image editor of choice.