Is Duncan a good king?

Duncan was a good king, that was before brutally murdered by Macbeth himself in the beginning of the play. Duncan was a generous man who wanted best for his kingdom and not himself.... unlike Macbeth. Duncan is shown to have been a good king as he in mentioned throughout the play when it comes to contrasting Macbeth to him. He was a strong, noble and capable of ruling the throne with people loyal to him and him trusting the people. The only mistake Duncan made in my opinion was him misjudging  Macbeth and his loyalty towards him...