@Dr. Koin, the Nalia example is just ludonarrative dissonance :p Don't look at Baldur's Gate for examples of good writing. Making characters matter but are also optional can be done, I call it "obfuscated relevancy". If you don't speak to Kaelyn at all for the entire game, you wouldn't know that it was her army that was waiting for you at the Fugue Plane. Talking to characters reveals more information about what is going on than would otherwise be apparent. You wouldn't learn anything of Nihilus if you don't speak to Visas or Kreia. But you would gain the whole picture in DA:O whether you speak to the companions or or not. Morrigan always offers you the choice at the end. Bishop from NWN was a weirdly coherent example - he betrays you at one point in the story regardless of your interest in him. He cites different reasons for this depending on your relationship with him, but ultimately always betrays you. (this isn't an example of obfuscated relevancy though, just a good character moment) That is GOOD, it shows that a character has their own interests and goals that may not align with yours and you have no way to change them.