The PDF for the Remaster Core Preview is now available. Seems to mainly include stuff relating to things mentioned in Rage of Elements, including the text of several of the new or renamed spells.
There’s a new rule on focus points that says “The maximum number of Focus Points in your pool is always equal to the number of focus spells you know” which seems very significant, though I’ve seen clarifications elsewhere saying that it’s still gonna be capped at 3. The limit on refocusing to just once is gone, though.
Given that thunder strike seems to be a spell and not a cantrip, I don’t think it’ll replace shocking grasp.
Edit: As for the Wizard, they also explicitly stated that your GM may add spells to that list they deem thematically appropriate, so there’s a lot of wiggleroom.