You overestimate LK too much and some of your imformations are flat out wrong. LK has never enslaved Yogg. Yogg even knew that soon LK would know that he himself wasn't out of the cycle life and death. LK also has never wage full war against Yogg too. Yogg was imprisioned. LK was also vulnerable to mortal's weapon like plague bomb from forsaken. He was powerful but not to the level of KJ or Archimonde. Archimonde could destroy the whole city of magic by a single spell.. LK couldn't that for sure. DW was also much stronger than LK. He fucking broke the world. LK may not even be the best necromancer because necromancy belongs to the legion in the first place and Kil'jaden taught that to him.