This actually brings up a good point. Does this affect IMAP users or any users that not using an Google Gmail App? (iOS, Web, Android, etc) My guess is no?

Unless Google rewrites the mails I'd say that IMAP/POP users shouldn't be affected by this.

I disabled images in emails too. It never is something interesting and almost always it's some kind of marketing/advertising nonsense.

Oh, and I don't use the web frontend to gmail as it really got confusing. Where is my inbox that shows all the mails I got and not only some categories?

It's quite simple to reset gmail to it's normal, older inbox. Hover your mouse over the word 'Inbox' in the list on the left, hit the down arrow, and you get a list of different inbox styles to try.

Plain text is great for ASCII. But try reading a plain text email in a right-to-left language with English words (like technical terms, abbreviations, etc) between sentences. I usually have to copy-and-paste it into Word and do some formatting before it becomes comprehensible at all.

I like HTML and being able to emphasize points in my email. I also like being able to like bullet-lists. Apart from that, I keep things clean.

And I've dropped gmail for fastmail since gmail stopped being good a few years back.

So yeah. You may be an outlier, but there are lots of outliers out there :)