Of course every path gives enough content, but that wasn't the question. The question was which path is best suited for the story branches.
Sure, Warrior gives an exclusive Elin scene and Mage an exclusive Aurora bit, even Bookworm translates some Iris and elven dialogue, so its not an entire disadvantage.
But overall? Bookworm gives more options to the youngest sister that the other two classes simply not have. The entire vampir plotline is missing. You can compare the classes with each other and notice larger or smaller differences and point them out.
Sure, if you undermine the entire gameplay, then it matters even less what to pick. Why even bother responding, then?