I fully understand that opinion - it is a big pain point for many users. Inside KDE, our VDG (Visual Design Group) is working on ironing out those inconsistencies and visual problems. It's a gigantic task, but I do believe we are making progress - especially System Settings has been getting a lot better lately. They are also working on a evolutionary update to our default 'Breeze' design theme. Check it out at https://phabricator.kde.org/T10891.

(And if you do find specific problems e.g. regarding margins or fonts, please report them on bugs.kde.org, and we'll take a look.)

Nate Graham blogs about these types of consistency improvements every week. Lots of screenshots to show what has improved and what features are coming. Well worth a read. I think this shows the progress you are hoping to see.

https://pointieststick.com/

These posts are indeed great.

PopOS is really impressing me

That's GNOME.

It is, but the adjustments that they are making to it especially with the PopOS Shell to build in tiling window management on top of gnome has dramatically improved the experience (for me at least).

Default GNOME theming has been quite atrocious (to me), but I've been using Arc-Dark with Papirus icons and Noto Sans fonts (usually already packaged in Debian-based distributions). I couldn't be more satisfied, and they play well with Nord (from Arctic Ice Studio) color themes.

One of the most important design principles is consistency. Unfortunately that's an objective which is difficult for open source to fulfill. It would be great if the desktop environments themselves took the task of providing a couple of unified themes out of the box, where the colors, icons, fonts and everything else fit together.

Why do you want to attract uninterested users who's interested are primarily superficial and not aligned with the core values and spirit of linux/foss? This is how you breed corruption.

I think you and me see different values in linux as a platform. What I want is for linux to be a true alternative to windows or macOS for all users - not only the tech-savy. The goal should be for someone like my mom or my wife to be handed a linux based machine and for her to not see it as a scary thing, but as a viable daily driver.

I'd argue that your comment is somewhat elitist - what does it even mean to say that someones interest are "primarily superficial and not aligned with the core values and spirit of linux/foss"? Plenty of linux users already care about how their interface looks, that does not mean that they don't care about open source.

I'm not meaning to be elites in the sense that i'm trying to look down on certain linux users. But if someone is going to use linux or not use it at all based just on how it looks then they don't need linux and can use a regular desktop os just fine. Linux is important because of how it is used technically to build software systems and that it is open source. If you start bringing on users that don't have that interest then then it is just another web/chrome platform waiting to be commercialized and have it's true purpose undermined. Take Canonical to the extreme. Not everything needs to try to grab the attention of random person off the street.

That sounds like a personal goal? I'm not sure I see any necessary reason that linux exist solely in either category (open-source true purpose, or popular desktop). Did I miss the argument?

I honestly do think you missed it and it's been laid out by my two comments. This isn't a personal goal of mine it's just how I see the economics of it. People that want their grandma/gf to use linux as a desktop - that is a personal goal. None of those people give a shit about using linux or they would already.

Read more -still not getting it. "Breeding corruption" is a throwaway line. How? What happens? Folks use the software in some way, that interferes with the open-source users' own use? I can't see that happening.

It's not the users the cause corruption it's who builds and desires to take control of the system. If billions of people are using something it becomes corrupt because of the immense value of billions of users attention. Looks at every tech company. Spying, ads, censorship. Taken to the extreme these goals are counter to each other. Just look at what Canonical did when Ubuntu got a whiff of becoming a desktop os. You could call it 'selling out'. It's a very common, perhaps inevitable, consequence of popularity.

And what does this do to open source forks of the code? How does it affect those developers at all?

I guess I'm obliquely commenting that keeping the project small and in the hands of open-source developers, may be pointless. Otherwise, why agonize over what others are doing with it? Either we want others to use the open-source version too so its a popular desktop with lots of attention, or we don't and becoming a popular desktop with lots of attention doesn't affect those open-source die-hards at all. Either way, a successful project becomes popular on a lot of desktops.