On one hand I doubt many characters have enough cantrips to require an entire "separate panel", but on the other hand I would also love to see them grouped separately from the rest of the spells for increased visual clarity.
Test scenario: Shadowheart at level 4 with WIS 18. Her spell panel is completely packed with all sorts of domain-specific rubbish, and considering how often the party might benefit from Guidance, this alone would result in a big improvement.
