Currently Paladin's Cure is extremely negligible at end game. Cure is the single ability that most separates the concept of a Paladin from just a plain Knight. I think giving Paladin Cure II would be OP. I suggest making a combo of
Spirits Within ---> Cure
resulting in Cure doing 2.5 times its normal heal amount. It would not be spammable because of Spirits Within 30 second cool down and it would nicely fit the general combo system that the game uses.