I suggest some changes:
- Lay on hands: come back to the old way, with the points defined by the paladin level and the Charisma bonus.
Right now,I understand that a paladin of Level 10 with Charisma 20 would have ten uses, with 100 points to heal or damage undead, and she could use twice per round with touch attack (I understand healing would be standard).With the old rule, she´d have 50 points ready to use in just one round, both for healing or striking. In this way it would be more useful as healer, and would support her ability to kill undead creatures, getting a better paladin for combat with a very specific kind of creatures.
For the Remove tree, it could be used the Positive Energy channeling.
- Spells: get the paladin a spontaneous caster, as the sorcerer.
It´s not just the use of Charisma, but the idea of the paladin as a chosen one of her god: a cleric has to pray to get divine power, but the paladin receives it directly: smites, auras, divine grace, etc.
Other option would be converting the spells in supernatural uses, as Detect Evil, but with the use limits of the spells, with number of supernatural uses based in the Charisma score.
- Smite evil: change the damage based in level for d6 of sacred energy, using for example the progression of the rogue.
I feel that most of the paladin features are defensive or related to her inspiring function (with the auras). But as she is a holy warrior too, I think that she should have more hitting power. With all her features, she shouldn´t be as good as the fighter killing evil enemies, but I think that she still should get a bigger difference with a warrior, for example.
Since with this option she would be more powerful, the smites per day would remain the same.
I'd suggest decoupling the Paladin from Lawful Good.
Make it more of a Holy Warrior. Since the days of 1E we've had the Anti-paladin idea out there, lets make it a starting PC option.
Not a knight - the fighter has that down pat in the right build, but a divine champion. 4E has one thing right here - there should be a paladin for every deity, just as there is a cleric for every deity.
Specific rules changes to do it would be to simply change anything that says 'evil' to opposite of the character on the good/evil -OR- the 'lawful/chaotic' axis.
For neutral aligned? Not sure here... I can see an argument that even for divine champions of any deity, true neutral should not be an option - the crowd that says neutral is anti-devotion. If we imagined a deity all about perfect balance, and say... Paladins of this deity, in effect Paladins of Taoism... Where is their opposite? Perhaps an argument that "A paladin can be of any alignment other than true neutral and devoted to any deity other than one which only takes true neutral" would have some merit.