Going to repost what I said in the Beta thread:
Player paladins are holy light-worshipping protectors of the innocent. Their gameplay, armor, spells, visuals and in-game lore are based entirely and solely on the concept of the original Silver Hand paladins, and this does not, nor ever will fit any kind of Troll. Look at the Sunwalkers as an example: Blizzard touted them as being their own separate thing, "they're not really paladins, they're Sunwalkers". But the reality is that in terms of gameplay, presentation and hell even lore now, Tauren Paladins are not sunwalkers, they are Silver Hand-style paladins. And it doesn't suit them at all.
So it's all well and good to say, "hey they're Prelates, not Paladins" but at the end of the day they are going to look and play exactly like a Silver Hand paladin, casting Holy Light and Hammer of the Righteous. Calling an apple a banana doesn't make it a banana.
In lore there are no Troll paladins, there are no Tauren paladins; there are Prelates and Sunwalkers, but you cannot play as a Sunwalker or a Prelate because the playable class is only portrayed as a light-worshipping Silver Hand-type paladin. Player paladins, whether Human, Blood Elf, Tauren or whatever are only one thing - normal Silver Hand type paladins. "Sunwalker" and "Prelate" are just empty words, because there is nothing that differentiates them from actual Paladins. A Troll paladin would not be a "Prelate", they would be a regular Paladin. And that does not fit the race at all.
They all wear the same armor and use the same spells. If Blizzard were to bother giving them their own spell effects and names that would be a different story, but as it stands Sunwalkers and Prelates do not exist for player characters - there are only Paladins.