Just because he had his mind set doesn't mean that he wouldn't have conflicts. It wasn't like he enjoyed attacking ORB either.
Also, what's wrong with a character who doesn't have "conflicts"? People who just like Kira & his ilk are morons anyway.
Those kind of monotone conflicts which lead nowhere are the ingredients for a dull show and not an engaging one.
This point is proven true by the very reason that Heine has so many fans as he does. People are tired of idiots like Kira who keep asking themselves why they fight yet do it anyway.

Edit: Oh and all Kira fans just like him because he has the most overpowered suits, everything else is a lie.