Sure, but we all know 100% that Diablo is coming… Mephisto is probably paving the way for him. Original concept. 
IainM4k is right tho. I remember devs describing Paladin as the class that meshes together the overall action D&D fantasy in D2. It’s pretty obvious: they buff everyone - so does Barb, but can Barb directly heal you? No, sir. Raise your resistances by 120 thank you? Uh-uh. Mana regen you’re welcome? Nope. Turn on Vigor, we all zoom together through the catacombs, no concern for stamina. It was more potent as a concept than in general practice (except in early game)… but… that truly-co-op feel was there, and you could tap into it if you chose to.
Then came cookie-cutter Enigma/Hammerdins (Blessed Hammer wasn’t a real spell before that) but that was a weird, late chapter. It doesn’t count.
Look at the iconic poster, it says it all:
https://blzmedia-a.akamaihd.net/d3/media/artwork/artwork-diablo-print-full.jpg
Paladin completes the fantasy.
I have a vague memory of reading something similar specifically about D2 Paladin, that he turned away from the order because of its mistreatment of locals - that he vowed to stay true to his principles in order to protect the innocent, even from his own co-religionists. Hopefully I’m not blurring the two.
Crusader was an almost pure caster, rather disappointing. I don’t like “WOOSH”, I like “THUNK”. What good is a scepter if you can’t make it “THUNK”?!