A Number Of Fedora 27 Features Get Pushed Back To Fedora 28

[Gusar]

And the buildtimes for Qt can easily be longer than entire Linux kernel.

There's nothing weird about that. You're comparing two very different beasts. The kernel is very low level. A customized config builds in less than 3 minutes on a modern CPU. Even a generic distro kernel won't be much, probably around 20 minutes. A web engine though, that's an entirely different world. Different language (mostly C++, while the kernel is largely C), plus the web has gotten extremely bloated in the past few years.

There's just something seriously wrong with Webkit/Webengine....

Not sure if it can be classified as "wrong", but.. on my Haswell i5, it takes less than 20 minutes to compile Firefox Nightly (around 14 minutes for the 52 ESR version), but it takes almost two hours to compile Chromium. Since Webengine is basically Chromium wrapped in Qt, it's by far the largest component of Qt. How long does it take to compile the rest of Qt? Longer than GTK for sure, but can't be insanely long.