Cleric 2 isn’t Crucial. Its beneficial.
Might as well break down Clerics.
C1 Cleric- Is the base of 5 heal squres x 2 overheat. This is 10 heal tiles which means you put out 50% + X, healing every 22’s. 2.2% healing per second if you break it down over CD.
C2- Cleric, Now you’ve gone to 10 heal squares x 2 overheat. That’s 20 heal tiles which means 100% + X healing every 22’s. You’ve doubled the effect basically. Divine Might means 2 more heal squares to 110% + X
C3 Cleric is 150% + X healing every 22 seconds. That’s a 50% boost from C2 Cleric. Divine Might means 2 more heal squares to 160%. Good amount of healing if you lack Priest. Basically 6.8% healing per second if you break it down over CD.
Krivis, starts at rank 2 and provides Aukuras. This isn’t a percentage but it’s a strong amount of healing regen when you consider that it also reduces enemy accuracy. Aukuras works well for stationary encounters as while it heals it also doubles as damage mitigation vs physical damage (and a small amount of fire resist) as a result of its accuracy reduction. The long cooldown time makes it not very practical for areas where you need to move around a lot (which is a fair amount of areas).
Finally there’s Priest which doesn’t get a heal until its C2 which is rank 3 at the minimum.
Going to 28% + X health, it can affect 5 targets which lets it put out 140% healing prior to Divine Might over its 30s CD in addition to C1 Clerics 50% every 22s. Priests also can resurrect and prevent death. When you break it down over CD. C1 cleric - C3 Priest has almost the same heal output at C3 Cleric. C2 Cleric- C3 Priest has more healing than C3 Cleric as a result, and C3- Cleric - C3 priest is overkill.
Cleric c2 isn’t exactly crucial as
C3 Priest alone will have more potential healing then C2 Cleric - Bokor for instance let alone C2-cleric, C3 priest. Likewise C2 cleric - C1/c2/c3 Krivis has more healing then C2- Cleric bokor.
There’s a healing Hierarchy, C2 Cleric is an easy way to get a lot of healing within the first 2 ranks since it doubles the base. Linearly speaking Priest C3 (rank 4) has about the same healing output as C3 Cleric (rank 3) but with a lot more health related utility in Resurrect/Revive + the mitigation of Aspersion. At the same Tiles work well for individual healing concerns so C3 cleric is more flexible when it comes to individual healing despite their overall party healing being about the same.
Now if you’re picking Diev or Bokor, These paths take you away from the healing output of Priest which doesn’t come on line until C2 Priest and C3 priest. Likewise Aukuras really wants 10/15 levels put in it to maximize its mitigation properties. These builds should grab C2 Cleric since it’ll ensure a basic healing efficiency, particularly for Bokor since they can reduce the cooldown of Heal, increasing its effective health per second contribution.
Tl;DR.
-Cleric C2 isn’t generally crucial.
-Krivis/Priest healing is bad until their C2’s (rank 3). Bokor/Diev are rank 3…so you get Cleric C2 to pick them up at rank 3.
-C2 Cleric + C3 Priest has very high heal output (more then C3 cleric by itself). It’s one of the few builds in the current state of the game that isn’t impaired by backtracking
That and Safety Ground is nice.