That is true. He seemed like the most evil guy until the very end. I started to feel bad for him too. But having only one person who knows he's innocent is interesting, and they will still be able to to talk about rehabilitation with him dead and Bryce dead as well. But I agree it may have been a stronger topic if he was alive.
I am concerned that the fact that they killed him will make season 4, season 3 : 2.0 if you know what I meant