I agree about everything you said but if we stick to the lore, it is more of a handicap than an advantage.
When lore is keeping us from having diversity and is making things stagnant, the lore needs to be changed but just enough for it to make sense and fix those problems.
With everything that happnened with Arthas, Deathwing, The Sha, Draenor… we even defeated the burning legion for heaven’s sake XD All that must be enought to have made us powerful enough to permanantly summon more complex demons.