I think we can all agree that paladins exist in Pathfinder and literature as both defenders and smiters of evil.
Keep in mind that the new core rulebook has space considerations and time considerations.
Pathfinder 1E focused on Archetypes. One of the reasons they started 2nd Edition was to introduce the archetype concept into the core rulebook.
So if you can potential modify a class through archetypes, feat choices, skill choices and even stat choices you pick a place to start introduce the class that way and then in further material introduce other variants of the class.
So we start with the tank paladin in the core rulebook. In the 2E advanced players guide you introduce an avenger type paladin, a ranged paladin that is dex based and maybe a healer based paladin trades some offense for even more protection.
The point is we are limiting the paladin class we are just limiting what goes in the first book.
Personally I think one thing I would like to see is to divorce the paladin reactions from alignment. Have them be different orders so you can choose alignment based on your paladin view, choose a reaction based on how you want to play the paladin (I love the debuffing variant) and then go into feat choices.
Plus Goblin Paladins are awesome. Fiery Justice for the Great Fire Goddess of Flaming Fiery Fire! (With some ancestral adoption to get produce flame for fun and ranged option)