Given that options are organized hierarchically and have type annotations, it should in principle be straightforward (though a decent amount of work) to have a general tool for guiding users through the options available in the install process. Bonus points if it can automatically partition/format drives based on the filesystems options.
A while ago, I made an attempt at doing so using xulrunner and the XML output produced by the manual. You can find my attempt in nixos/gui directory. This tool was mostly made to provide a visual tool to browse the result of NixOS configuration file as nixos-option is providing. (It might even rely on the xml output of nixos-option).