Yes, I love it when love triangle are used as a vehicle to present a moral choice than merely having it be about ‘feelings’ and superficial attraction. 😀 Though I am surprised since I thought you didn’t like Austen. 😛
For the A likes B but B likes C sort… I would usually only like it if B’s feelings are reciprocated and B and C are in an established relationship. Otherwise if A is presented too sympathetically, I will get frustrated with B for continuing to hang onto C who is clearly not interested instead of giving A a bit more consideration.