OK, I'll bite, why no Paladins? If it's because "Oh, they're broken," well, Clerics are far, far, FAR, more broken. And Alignment? Dude, if this is 3.5, Lawful Good doesn't mean lawful stupid for that matter, and you could always go with the 4e clause that a paladin of a deity is the same alignment of that deity. And if there AREN'T any evil characters, there shouldn't be that much alignment conflict unless you're dealing with dickish as hell players... or a douche of a GM who just wants to make the paladin fall. For that matter, Cleric's and Druids overlap with the Wizard and so do fucking Sorcerers. Hell, BARDS overlap with Wizards. Barbarians overlap with Fighters. Why not ban Barbarians, or Rangers?
So yeah, the reasons you gave ain't good ones.
Mord - Paladins in D&D are basically the equivalent of the militant arm of their church. They are the defenders of their faith, and according to class roles, are basically Clerics with Swords. Reality is that a good Cleric build will just wipe the floor with any Paladin build. Clerics are full on spell casters that can wear heavy armor, have more health, and can heal. Yeah. Paladins are basically fighters that can patch themselves up a bit, and SMITE EVIL. That's really it.
