Everything went well, until I added a customized kernel (I had installed the VM to do some kernel experiments after all). The boot menu suddenly was not very useful anymore. After selecting "advanced options", I got the following:
There is no such thing as in old GRUB where "Esc" got you out of gfxboot mode and into text mode. The command keys, like "e" for editing the current selection and "c" for a GRUB2 shell (something even more hellish than the old GRUB shell apparently) work, but you really need to know this, as there is no indication of that.
So I wanted to get rid of the gfxboot stuff. I don't need fancy, I need it usable.
Booted the VM, logged in. "zypper rm grub2-branding-openSUSE" followed by "grub2-mkconfig > /boot/grub2/grub.cfg". Much better:
Now that "Distribution" string in there looks completetly redundant, so getting rid of that will help, too.
Again, it is in /etc/default/grub, variable GRUB_DISTRIBUTOR. I see that in the grub2 rpm package, there is only "openSUSE" instead of "openSUSE Factory Distribution", so it might be put into the config by the installer or something. I'll change it to just "Factory" (to distinguish between other openSUSE installations). After grub2-mkconfig, it looks almost good:
Just fixing the Factory string would probably have helped also, but it still would fail the server test, so plain console will stay my favorite for now.