Paladin has good "knight in shining armor" vibes that make its narrative consequences less dependent on the deity. It's the kind of place that'd be a good home for a variety of "elite warrior" figures. Cavaliers, samurai, tribal champions, knights in shining armor, ronin, blackguards, death knights, dwarven thanes, shield maidens, etc., etc.
Cleric depends so much on the god and this "heal and buff" legacy that they don't have much of an identity apart from those two pieces. And if you distribute role responsibilities and you distribute your world's religion...you loose most of the reason for having the class.
The world still has priests, o'course, we just take the divinely powered adventurer and distribute it to classes that fit the actual vibes of the gods associated with the domains rather than one whose entire schtick is to cast spells themed to a kind of god.