CapnZapp
Legend
In theory, I agree.I hate the whole "Well, it's an NPC, it's allowed to work with different rules" concept. I like a world where the physics of magic work the same for PCs and NPCs alike.
In practice, however, the idea completely falls apart. I am not interested in building a high-level NPC spellcaster from the ground up ever again. The effort simply isn't worth it.
The basic truth is that mid- to high-level characters are incredibly complex. That's a good thing for me, since I enjoy how D&D makes building your character not only a role-playing challenge, but a mechanical challenge as well.
But as a DM, I simply do not need that level of complexity for a critter lasting two rounds of combat. In fact, I absolutely refuse to DM a game that doesn't simplify high-level monster building.
That doesn't mean I can't understand if players get miffed if NPCs display powers they themselves simply cannot replicate (or loot!).
4th ed went too far in this direction, making up stuff no matter how implausible.
But I'm happy with what I've seen of 5th ed monsters so far.