Really like the ideal of making Holy Retribution not having charges.
I do not like the favored weapon because there just isn't enough of them. Maybe just a +1 to hit and damage like the Tempest tree and Kensie tree, but tied to paladin spell levels. IE second tier(first tier would be a problem since paladins do not get spells till level 4) ability to cast 1st level paladin spells, up to fifth tier ability to cast level 4 paladin spells or something else to limit it to paladin levels.
Regenerating turns. I think it is to low because clerics do not get it till tier 4. Maybe remove Passion and put it there instead?
I personally like my level drain immunity.