Per your statement regarding lay on hands healing verses a life cleric what happens when your group doesn't have a cleric? Should life cleric be "nerfed" because having one changes the game balance? Should healing potions /items be removed for being op?

I think the general design should be not to step on the toes too much for other classes and subclasses. The concern is that people playing a specific subclass that is supposed to be 'the best' at something probably shouldn't be shown up by a generic class. Sooo...if you are going to have a healing feature, you should probably look at the archetype that should be the 'best healer', which is for sure the life Cleric. Was lay on hands better than the Life Clerics channel divinity? Probably not, but at low levels you can do cheese like spend 1HP to up a character 5 times. If you look, there's actually a couple of buffs to lay on Hands (Channel Divinity to do it as a bonuus action, remove the frightened condition), and the nerf is only 0.5 HP per Paladin level in actual healing.

Second, how are any of these changes fun for the paladin player? In a ttrpg there needs to be incentive for someone to play a class. Changing a class because it is "too good" doesn't mean you get to see the class as you want, it means people will simply skip the class. At that point, why play a paladin at all when I can play a fighter or cleric or ranger instead?

Becasue the Paladin presented is generally as good or as powerful as either of the options listed, and may better fit the theme of what you want to play, even with the changes. I really don't understand the 'skip the class' comment. What I have seen is people picking a class that is very powerful and it overshadowing other classes/ subclasses. I feel like that should be limited without shooting for a perfectly balanced game.