The problem with Guardian Saint is not the hitlimit (as you can get up to 21 hits with the gem and Divine Might) but rather the duration:CD-ratio (60:90 seconds without Diev/Krivis).
I personally like the effect on my Kabbalist, but in most cases the skill probably isn’t worth the cast unless it’s really necessary for a certain member of your group to stay alive.
I rarely use the skill currently,though, because it’s either useless if the guy has enough defence or insanely dangerous if the guy has low defence or a level penalty. Guess it will become more useful later on, but I don’t really see a reason to keep the skill except that it’s the only C3 skill of the Cleric. Maybe the developers will come up with something to make it more useful…
A good sideffect is the boosted SP- & Stamina recovery rate,though, which helps a lot in combination with buffs like squires foods/Zeymyna statue e.g., so unless your target gets excessively involved in taking hits, you get a decent boost to your recovery.
About your build:
Cleric C1 is enough if you know how to time your healing & your team has potions/Aukuras scrolls at their service[There’s always the solution to bring 2 Clerics along,though; one supporter and one damage dealer e.g. who’s most likely at least Cleric C2]. The real problem comes with people who have high max HP as your Heals probably won’t do much for them, while people with low max HP will most likely have enough healing from your 10 Heal tiles&Mass Heal (as it nearly heals 30% HP every 30 seconds, which is ~equal to consuming 4-5 Heal tiles).
10 Heal tiles every 22 seconds + Mass Heal means ~ 40% HP recovery for every party member [+ some extra based on your INT&SPR] within 30 seconds. If people lose more HP they’re dead anyway or their equipment just sucks.
Revive will also help with survival, as well as Capella&Stoneskin, which can now help cover the weakness of taking Cloth Armor&Leather Armor [ as Stone Skin now allows you to take 20% less damage from Slash&Pierce damage]; If used tactically, you can just wear Cloth armor and enjoy 25% less damage from strike type and 20% less from pierce type while only recieving normal or 5% more damage from slash type[depending on how weakness and resistance get calculated].
With the new defence scaling vs attack scaling, that’s worth a lot of defence ,once you hit around 2000-3000 defence, to achieve the same effect.
As Barrier also helps with reducing incoming magic damage, Priest+Paladin is the best combination for party support, especially considering that Resist elements can also negate certain elemental damage/reduce it effficiently.
Just a small advice in the end: Take at least one point out of your Smite. This doesn’t hurt the damage much, but having at least level 2 Turn Undead will allow the skill to scale its certain-death chance with your SPR. This is certainly very useful when confronting devil and/or mutant type enemies 