OK. I see. You want monsters and NPCs to be created just like PCs are created. Geez! That would be a LOT of work on Larian's part because NPCs are created in the same way as PCs. They don't have Character Levels like PCs do. They have Challenge Ratings. So Larian would have to create all their monsters the hard way from scratch instead of taking already done for them monster stats and maybe tweaking them.
And I'm still a bit confused by this. The Goblin Captain has similar stats to the Goblin Boss. Goblin Bosses have roughly 21 HP with AC 17. He just doesn't have Multiattack and Redirect attack or a javelin. Right? Instead, he has the Warcry ability and Action Surge, I think. So how is that not playing by the same rules?
And the githyanki are slight variations of the D&D 5e githyanki. One is like a ranger version. One is like a rogue. One is like a cleric, and one is like a fighter. Aren't they playing roughly by the same rules?