Not.... really?
Teria is pretty average for a 3 star these days. She used to be obscenely broken, but cards at her level aren't as rare as she used to be.
Only reason she'd be banned is because most people don't have access to her, rather than actually being crazy broken.
As far as Guru goes, I'd honestly rather go against him any day of the week than Surstorming, Maana Cercei, Ymirah CR, or Kalindra CR.