The reaction for Temporal Shunt is taken:
when a creature you can see makes an attack roll or starts to cast a spell
But Grapples, Shoves and some Arcane Shot options of the Arcane Archer don't make attack rolls.
Would the spell remain clear and balanced if the text was changed to:
taken when a creature you can see starts to make an Attack action or starts to cast a spell
Which would cover those edge cases, I believe. Is there any balance or rules issue with this?
Best Answer
You have made the spell strictly worse.
The improvement provided by the house rule is going to depend one the frequency with which the caster encounters enemies using grapples and shoves, but even then, it is going to be negligible. Why? You already have other opportunities to use temporal shunt. In a combat that lasts 5 rounds, suppose a creature makes 7 attack rolls and 3 grapple attempts (one per turn for three turns). The house rule gives you three more opportunities to use temporal shunt, but you were already able to use it every round, so the house rule isn't really doing much for you.
So that's what the change improves, but what do we lose? The spell can now only be used when an Attack action or a spell is involved.
I don't think this is intended, but your wording now restricts the spell to being used for attacks made via the Attack action or a spell cast. The enemy makes an attack using their bonus action - you cannot use temporal shunt. The enemy takes an opportunity attack - you cannot use temporal shunt. Your rewrite of the reaction trigger restricts the use of the spell for little gain.
You have made the spell strictly worse.