Hi Dave, here's some unsolicited advice about writing (not about opinions per se): Do not let the wiser person be a spokesperson for your views. A reader will spot preaching a mile away. Instead, make the wiser person flawed in some deep way, so that s/he takes a risk in explaining to your protagonist how the protag is going wrong. Maybe even introduce some of the protag's flaws into the wiser person, so that the wiser person is actually trying to come to terms with his / her own dark side.

Best wishes with the novel.