In the subsection "Why multiclass" you list some of the drawbacks of multiclassing. Maybe it would also be worthwhile to point out if what build you are trying to make is supposed to be a full caster then single classing (with some exceptions like chanter/healer) might be better. You do touch on that fact with power level scaling, but in my experience this is more punishing for casters then for martial classes.

Fantastic thread - I can't believe I haven't seen this thread till now!