Although not needed, a GUI for the minetest.conf file when creating a world would sure be nice and convenient. It would especially be nice for those new to Minetest that don't even know about the minetest.conf file (or those that have very little computer skills).
We could also have two ways to create a world:
"Quick Setup" - Only decide what mods are used.
"Advanced Setup" - Decide what mods are used, and pop up a GUI for the minetest.conf file (at least for the settings that are not under the settings tab).