1. No Spell Making
2. Indestructible armor and weapons (ie no armor/weapon degradation in battle)
3. Limited types of spells compared with Morrowind or Oblivion
An honorary fourth annoyance is several lack luster quests, questlines and storylines.
My number one annoyance would be NPCs that talk to you with the same lines every time you get anywhere near them. However, I have a mod to stop that very annoying behavior.
There are however many nice improvements that keep me very interested in this great game.
Unless you're exploiting/maxing all three crafting professions-- I don't buy it. Perhaps for a stealth archer with a dual enchanted legendary bow, but for a melee class Master is not easy. I fought an enemy today that would one-shot me with a single arrow-- on expert.
I don't buy it either. Not when at level 41 a Bandit Marauder can on hit kill a level 41 character with 330 health. How is that easy? Claims that Master is easy are nonsense, in my experience.