As I understand it, Kragg's focus on his craft centers around arete, about making the best something he can, and that extends to making the best apprentice he can, and that to do that he needs the best material to work with so if he finds the perfect neophyte he'll teach them what he knows, but in this fallen and debased world he's more likely to have a Skaven hauling a wagon of gromril in front of him, apologize for all the grudges and then fall on the ground dead so Kragg doesn't have to kill the raki himself than come across as someone worthy of being taught by him. Is that a fair assessment?