There's a very simple solution to this : create your own post install setup program and stick it in ports. If it becomes wildly popular then a line could be added to afterboot to point users at it.
In the meantime I'm quite happy not answering X questions when installing OpenBSD as a firewall. You're also wrong about FVWM and HDPI screens. FVWM is very flexible, but a pain to configure (I use cwm). The majority of users still use 1080p monitors (go check the Steam hardware survey).
