I share the aversion to “Mussar” (ugh!) apparent throughout the site. There are two exceptions, though.
The first exception is the style of דברי יהושע by הרב יהושע הלר זצ”ל of Telz. If I remember his introduction there, he explains why the regular method doesn’t work. It’s like making everyone, of all different diseases and ailments, and whether or not they are experiencing pain, take a standard “pain-reliever” (I would add: Or placebo). That’s what happens in institutionalized Mussar, which may be another outgrowth of “Establishment”; another issue the site is busy tackling (לשיטתך?).
The second exception is the style of הרב שלמה ברעוודה זצ”ל, who was very into describing גיהנם, like דרשנים of old. Not so far from the Torah’s own style, as in בחוקותי\כי תבוא. If you stick to the source, you can’t stray too far.
While the Chafetz Chaim’s works are full of mussar all over, that is a different genre altogether, talking simple language to simple people, and I wonder if that’s what made him the leader of the simple בעלי בתים. I haven’t heard anyone group him with “בעלי המוסר”, even though he probably does the best job for most people.