u/Busy-Day-1582

The L9 Cleric in my game has had Crusader’s Mantle added to their Always Prepared list due to RP and plot. But with other fantastic Concentration spells competing for attention, they’re feeling like using it is not really worth it in combat. I’m thinking of allowing it to be cast with higher slots in order to increase its appeal. Should the damage die increase in size with each slot level above 3 (ie. D6 at L4, D8 at L5)? Or maybe an extra d4 every 2 levels (2d4 at L5). They have WarCaster and a good Con Save so would get great utility out of it