I seriously dislike window themes that try to look glassy, glossy, frosty, semi-opaque, shiny, metallic or any other “realistic” effect. The same goes for icons with 3d or realistic optics.
If a user wants those kind of things they can go to xfce-look.org and its ilk and try to find something that works for them. It only takes a few clicks in mx-tweak to change the theming.
As AVLinux, asqwerth and dreamer have pointed out, it is a lot of work to get a theme looking halfway consistent just across gtk2 and gtk3. Gtk4 keeps moving the goalposts and actively making it harder. Qt6 may or may not throw another spanner in the works. I don’t know if any of the devs have the time or interest to invest in getting a “skeuomorph” theme working consistently. Personally, I know I don’t.
I would have a problem if such a theme was to be the default in MX. Why would you purposely make the distro look like some kind of Windows 7 retro thing? To appeal to nostalgic users who grew up with computers in AK-47’s 90’s-00’s and 00-10’s eras? Is the current look of MX really the thing holding back hordes of new users from using it?
So, now a personal polemic: A window theme and an icon theme should be simple, consistent and yes flat(ish). The MX-comfort theme is an excellent example. Papirus icons are an excellent example. “Realistic” effects are an unnecessary distraction. Windows 8 only gets a bad rap as the precursor of all evil through of a combination of the stupid way they implemented the windows menu as a full screen and conservative backlash against the shock of the new. Theming-wise Windows 10-11 does a lot right.
As a final note: I’ve been spending my hobby time fiddling with a variation of the comfort theme. Sorry “skeuomorph” fans, if it ever sees the light of day you’re probably not going to be enamoured with it
Disclaimer: These are my personal thoughts and do not necessarily reflect the opinion of MX-Linux in general.