I don't know, OP. Honestly, I think "Repentance" is the climax of the entire suite. Specifically, I think it is the ninth movement, Restitution, the very one that most people seem to hate, that is where the suite hits its climax.
The whole song, really, gives me such great vibes. It's chillingly simple, and it's a remarkable contrast to the rest of the suite in terms of dynamics and mood. I love the reprisals of the "This Dying Soul" theme. The melodies are calming and catchy, the lyrics are reflective and interesting, and Petrucci's guitar solo is beautiful.
The ninth movement, starting with the voices, is so chilling that I can't believe people don't like it. The voices are an excellent touch, to show how widespread (yet at the same time, personal) the subject matter is. The section after the voices yet before the deep booming voice? That, my friends.. is nirvana. ^w^ They couldn't have done that part any better, in my opinion. It's where the whole suite turns from reflective to "Teach me how to be good," the theme which is prominent in "The Shattered Fortress." The booming voice is a nice addition, as well.
Overall, "Repentance" is an underappreciated gem, and the ninth movement is a key section to the Twelve-Step Suite. But then again, all this is just my opinion.