And I could say the same about the Avenger. Or the samurai or the runepriest or one of any other somewhere around 100-200 classes through all the editions and third party supplements.
Roleplaying alone is not enough reason to have a class. You can't force a player to roleplay through rules. If you do that, you end up with whiny players complaining how their character sucks because they can't do {insert random thing}. Or you get the 1st Ed Cavalier, which is basically a pre-video game bot.
Oh, I have no problem ditching the Avenger, or Runepriest, or even the Samurai. Though the Samurai is very flavorful.
I think if the niche filled by the character archetype is distinct enough then, yes, it does warrant inclusion.
No, you can't force a player to roleplay through rules. Which is why I said anyone who doesn't want to rp a paladin shouldn't play one.
I loved my AD&D paladin. Strictures associated due to code of conduct and alignment? No problem, I'm playing a chivalrous good guy.
Limit of 10 magic items? Dang...ah, well, plenty of other perks to make up for it. Tithing 10% of my loot...fine with me.
No associating with evil pcs unless it's for a really, really good cause? Fine with me, great way to keep those evil yet fashionable Drow out of the party.
Even without the lay on hands, protection from evil, and fearlessness, I still woulda played them.