The truth about KDE: http://firstname.lastname@example.org/msg88679.html
I also remember them coming to misc and inform the community and porters that KDE won't run on openbsd due to the use of a cool linux daemon to manage stuff.
They don't include Emacs (instead mg is in base, rewritten from scratch with a funny easter egg inside) neither do they include Libre Office. It's just a Makefile and some patches that are distributed. Package are a convenience for the users, and available only if the license is 'free' enough (i.e legally possible). They want to switch to pcc instead of gcc, I've heard that Theo does that.
OpenBSD's IPv6 stack is one of the most mature stack. I bet its code is already somewhere else (free license => not wasting engineering efforts). You might want to read about Packet Filter if your especially interested in tunning/handling IPv6 traffic.
Apache is actually an old version of apache, before the license sucked, and it underwent a lot of changes. Don't compare it to nginx. You can get it in the ports/package sysem if your not happy with the shipped apache.
As a side note, OpenBSD uses the ISC license when i can now. Might be worth looking