actualy Crono does speak once during one of the endings (Slideshow Ending)...

i actualy hardly ever kill Magus, i only did it a few times to see alternate takes on some of the endings, and NeoCracker is right about Magus' personality, he isn't inherantly evil but he doesn't care who he hurts on his quest for vengance, i believe it's stated as such in his Bio in the Strategy Guides...