I remember looking at some point, and Gnome had roughly 4x the number of developers that KDE had. If you want the best (most stable, most well tested, most feature full, etc.) programs, you basically have to use some Gnome programs. That was one of the deciding factors that pushed me to go with Gnome. If I was going to have to use Gnome programs anyhow, and they worked best with Gnome, then I thought I should use Gnome. My experience was that Gnome programs don't really play well with KDE, but that KDE programs generally work OK on Gnome.

I really like the customizability of KDE, but I like many of the defaults of Gnome. Unfortunately, if you don't like some of Gnome's defaults, it's real pain in the ass to change them. Personally, even though I liked a lot of Gnome's defaults, I absolutely hated some other ones. If it weren't for extensions there's no way at all I could use it. Luckily, some of the biggest misfeatures are so widely recognized that there are dozens of extensions to choose from to fix them. OTOH KDE's customizability led to some issues too. I remember having some weird interactions between things because settings A, B and C don't necessarily work well together. But, at least those settings are built into the desktop environment, and you're not relying on some random dude's hobby project for a critical system setting.

At the moment, I'm pretty happy with Gnome, and most days it just gets out of my way and lets me do what I want to do. That's something I never ever got with Windows. It was always a pain in my ass. And, it's something that was only ever 90% true with OSX. Great defaults, but that last 10% is a real pain in the ass. Gnome's extensions let me get much closer to 100%. I have to admit though, that I do dread the day that I have to upgrade it and all the extensions break.

You seem to have a really balanced point of view and that's good. I wanted to like KDE but on the other hand it reads as windows 2000 to my eyes and it bothers me. I did like some things about the interface but overall it felt too busy for me. I hadn't tried it in years until the recent plasma update and people raving about it and its customizability convinced me to give it another shot. One of the first things I did was try to customize the top bar and task bar to be cleaner. It crashed several times very quickly. That's a really bad first impression. The bugs I experienced immediately were as many as I'd seen in years of GNOME experience.

In a perfect world though, yes, GNOME would be more customizable, particularly the overview mode. I do not like it at all. On the other hand, it's not so bad I wouldn't just live with it if I didn't have other options. I do though. To launch any app not common enough to put on my dock, I use ulauncher. It's not the best but it usually works well as an alfred-style launcher app.

I hated macs until OSX and since then I've hated windows more. Just mentioning because I'm sure someone will read what I've written and think I'm a Mac guy. Which was true for a bit but I've grown to dislike macs a lot as well. Their OS is still better than windows though!