I wish they'd just hurry up and semi either Mask Change or Anki just so people would 🔥 with the "it's SR/UR, they won't hit it" crap.
As for hitting Spellbooks, Silent Magician probably isn't the card worth hitting anyway. I'd consider semi'ing both Magician and another relevant card (probably Secrets, possibly Fate or Master).
I agree with wall of d and d traphole to be limited, but for Mask change, I have to disagree with you (Mask change II is way more busted than Mask change)
They won't directly limit mask change or anki cuz they're sr and ur. Instead they'll limit the cards that support it like semi limiting decider or malicious to further slow down the deck. Then the deck will be too slow to compete in the meta.
As for wall of d, it can be played around if you play smart so it's not a problem.
Apart from trunade before an otk, there's no counter play for TTH,
Mask change will never be limited, even if it wasn't an SR. Heroes are one of the most popular archetype in Japan, and konami will most likely release the other mask heroes in the future, they won't shoot themselves in the leg this time.