I've been running Wayland gnome-shell on Fedora since Fedora 25, on a Dell m3800 and now a Dell XPS 15, both with 4K internal displays. I often connect to external monitors or projectors, either 1080p or 4K.
Wayland has better HiDPI support than X and has for a long time.
In order to make X work in any reasonable way you need to configure X to render at 4K all the time on all outputs and downscale using xrandr on 1080p displays. X cannot handle different DPI settings.
So there is no way for a game to bypass wayland and write directly to the fullscreen framebuffer? You're just stuck with an extra frame or two of latency?
I'm not sure how graceful the alt+tab behavior of this approach would be though.
This is especially true for people that prefer low latency over tear-free rendering.
Wayland requires* everything to be monolithically built into the display server (which is also the window manager), which means if I want to use a new WM (say, XMonad) I need to reimplement all of this stuff. Want screenshots? Build it into your WM! Want redshift? Build it into your WM! The result is that development effort will be wasted reimplementing "competing Wayland implementations" stuff that no-one actually wants.
Compare X11, where I could run an Xorg server together with any of a number of lightweight window managers, and the window manager is only responsible for, y'know, managing windows, and determining how the window decorations look. Xorg handles everything else, allowing a robust marketplace of competing WMs to arise.
* Unless/until they finally give in and standardise protocol extensions for out of process window managers.
? what? you mixed systemd with wayland maybe, everyone knows that wayland is a protocol, this is repeated 100 times in each thread , everyone also knows that most of X features are not part of wayland
For gaming, the latency is bad and always on vsync is horrible. They've fixed the 60Hz lock though, fortunately. This only applies to gaming though.
My primary issue with Wayland isn't quite so much that it lacks these things, it's that they seem to be of the opinion that there's only one way to do things, and any other use of the visual display system is wrong. I just have this weirdly oppressive feeling about my inability to configure it the way I want it, the same feeling I get from using Windows. Just... let me be me. I get that this is a non-technical complaint, and that it ultimately boils down to "it gives me the heebie jeebies" which isn't an argument, but it's still how I feel about it.