Just have a text config file that comes in a variety of preconfigured flavors ("x mode", "y mode"...) and then also offer a "make your own config" option too.

Most of the time, if I'm working in blender for example, I want some really sane prepopulated shader values and one size fits all rig values for sofas vs chairs, but sometimes I want to go crazy and make chairs out of glass and slime, etc.