Oooooooooooooor the paladin class he's referring two is the Diablo 2 paladin.The Guardian? If you're talking about the new Diablo 3 class, I recall they called it the Crusader, not Guardian. A quick search for "Guardian Diablo 3" reveals pretty much nothing (no characters or classes), but searching for "Crusader Diablo 3" comes up with all the details of the class.
If you must compare Diablo 3 stuff with WoW (which I don't consider a good idea at all) then Tyrael and the Crusader are most analogous to the paladin, yes. Come to think of it, I'd like Tyrael's wings on my paladin instead of the current Avenging Wrath animation.
Creating a new class along those lines for WoW wouldn't really work. The biggest issue is that the last armor "tier" slot to fill is mail, which means the class will either be agility-based or intellect-based since there's no way in the Twisting Nether that they'll add strength to mail gear. None of the holy warriors in WoW have ever been based on agility, although a few have been based on intellect. Thus, if the new class were to have a holy vibe then it would need to be entirely based on intellect to work. That would cause problems since we've already got quite a bit of caster holy stuff between priests and paladins, but I suppose Blizz could get more creative behind the premise if they really wanted to especially since WoW doesn't have any casters who are actually viable DPS via holy damage.