It would be a awesome feature to add items via CraftTweaker
and load the required resource maybe over the Mod "Resource Loader"
with Commands like in Quadrum or ContentTweaker just in Minecraft 1.10.2 ?

This is a good idea, however due to the load order of this mod, and the priority on reloading it is not a good candidate for a feature in the main mod. An addon may be released which provides this functionality in the future.