The groundwork has already been set to make high spirit builds useful with a few interesting buffs scaling off of spirit. Obviously the primary buff being stone skin.
My suggestion is that you continue to develop spirit as a support stat.
Maybe give blessing a 1/4 spirit scaling so it might be more reasonable at later levels.
Could also scale at a fraction for last rites or sacrament.
To aid in the solo leveling department and overall team usefulness, add an ability to cleric that adds a small portion of the clerics spirit to weapon damage.