One thing to note is that a build doesn’t just constitutes of 1 class only. Having a paladin 3 doesn’t mean that that paladin can’t take Priest1 for revive and/or druid2 for Sterea Trofh in R8. We have to balance classes and skills based on the mentality that they are used in conjunction with other classes within the main cleric tree.
Hence you see many C3 skills are strong but yet not strong enough to stand on its own without needing another skill to compliment it. It gives a weakness that will be covered by other classes. This is the reason why I don’t support Ausrine having a CC immunity, it shouldn’t be a "stand-alone’ skill but rather a skill with an opening in which other classes can fill.
To make paladins more wanted in ET, what they need is not more damage mitigation, rather more party buffs or enemy debuffs that helps the party kill faster. This is why dievs and krivis are favored in ET, they either reduce cooldowns (make party cast skills more) or extends buffs (extending ausrine/retreat shots etc).
Approach the changes of paladin in this way.
C3 Conviction
Attribute that increases the AOE attack ratio of the skill by 2 per level, max level 4.
This increases the AOE attack ratio of conviction to 10 at max, making it a good physical aoe skill in which the C3 paladin can count on rather than a miserable 2 aoe ratio skill. The aoe debuff this skill gives also helps the party’s magic casters to deal more damage.
C1 Resist elements
AOE wide debuff that lowers magic resistance of mobs by up to -150 magic resist at level 15. Reduces cooldown to 1 min instead of 2 mins.
Just these 2 alone will make paladins more party friendly and a consideration for ET.