I'm not sure the minimal install resulting in a blank screen is actually due to lack of non-free graphics drivers. While the GUI is an integral part of Windows that Microsoft forces upon all users, in addition to giving users the choice between a number of different Desktop Environments, Linux can be run without any gui at all, much like MS DOS from the pre-Windows days. I'm pretty sure the minimal install of Debian skips installing a GUI of any kind, leaving you with just the command line. If you actually want a GUI, you need to include one of the Desktop environments at the select and install software step of the installation or manually install one post-installation(I believe most recommend either Gnome or Mate for beginners in need of accessibility.
As for the installer itself, as someone who installed Debian many times prior to going blind, I do miss being able to use up and down arrows to scroll through menus in the installer and while the numbers can be useful for quickly selecting a known option, I think a hybrid approach(or at least a quick reference that could be used to look up the numbers for appropriate options prior to launching the installer would be nice... I do agree language selection and keyboard layout selection might have too many options for a single list to not be cumbersome.
