More choices in PvE?

Every time I play in the wilds area and such I keep hearing Saidra...or whatever her name is, the leader of the shining blades tell me that when I see for my self what the White Mantle do, I will have to make a diffucult decision?

But what decision could I possibly make? It seems my character makes the decision for me, but I would rather stick with the White Mantle and see what happens...

Anyone else think we should have two different routes to choose from at that point so we could also play as a member of the White Mantle and start slaying the Shining Blades?

I'm not sure how far into the game you've gotten, but it's safe to say without spoiling it that would be difficult to play as the White Mantle for storyline reasons later on.