Originally Posted by
Fleugen
--And when you 'keep an eye' on someone, do you willingly look at their subjects and say "Yep. This one's good." and let them in because they say "I wanna be a paladin!"? No, you WATCH THEM. You KEEP AN EYE ON THEM. You realize that their kind joining you is uncommon, and if a sudden surge of them comes flocking to you, you get suspicious.
--The Forsaken are against the Light. The Argent Crusade is against Undeath. The only thing keeping the Argent Crusade from storming Lordaeron is the fact that the Forsaken are part of the Horde, and the Horde have proven trustworthy. Lately, Sylvanas' actions have proven she is not exactly staying within political reason with the rest of the Horde. Therefore, the Argent Crusade is more inclined to refuse help from the Forsaken, and the Forsaken have never liked the involvement of the Argent Crusade.
--And if a Forsaken wakes up one day and says "You know what, all this Undeath stuff isn't for me." and goes to join the Argent Crusade, do you really think he's suddenly going to come back one day as a preecher of the Light? Let alone not get torn to shreds by those who aren't inclined to believe him?
Technically, Tauren are Nature Druids. They aren't actually Paladins; Again, game mechanics trump lore mechanics. Tauren Paladins are actually Druids who follow An'she. (The Sun) But for gameplay reasons, they needed them to be Paladins to balance the classes together. Troll Druids have easily been explainable, as we've had Trolls who would shapeshift all the time. It was cultural only that the Trolls chose to follow one Loa rather than many.
Forsaken are actually 100% AGAINST the Light and all it stands for. The entirety of their lifestyle is on forsaking the Light and it's teachings. Undead can technically be Paladins, yes, but they essentially turn their backs on the Forsaken lifestyle if they do. And in doing so, they are not a part of the Forsaken.