If the engine misbehaved in a previous flight that day, there is a serious question of the pilots competence. You don't go flying with passengers knowing the plane isn't 100% at take off. In addition since the pilot knew there was potential engine trouble he should have been prepared for it. Instead when it happens he stalls the plane and kills everyone on board. Sounds like repeated serious pilot error to me.
I don't know any specifics about the case, and wasn't really commenting specifically on the case. I was speaking generally about the kinds of things that can get pilots in trouble. I did not even read the article past the specifics about the woman's state of mind.
I do agree with you, in any case.