That's pretty much what I do too. Zevran makes the compelling argument that Harrowmont can't watch out for his own safety and appears weaker than his rival. But I side with Behlen for other reasons too (besides meta-gaming). Each of my main Wardens (Cousland, Amell and Tabris) are mainly here to get the Dwarves assistance. Behlen supporting more trade with the surface is also a plus.
But I admit that Behlen's want to shake up the rigid class system isn't really apparent when you first play.
It's apparent enough if you play the dwarf noble in the beginning. You kind of have a choice to be a pompous *** or a populist, and you see where Trian or Bhelen fall on that account (you even see Rica coming out of his room, I think). I agree though that it could've been done better.
That said, it's funnier to be pompous. I like the idea of an Aeducan like this being humbled through the rest of the story. You could even play it as a redemption story, where you realize later that Bhelen was a better guy than either you or Trian. Or play it as a straight revenge story, where you become even worse over time. lol
Lots of subtle ways to roleplay.. one of the good things about this game.