I'd like for everyone to be somewhat unique, and to bring their own strengths to each fight. That, and it'd be nice if they all stayed within their (canon?) class, i.e., Nowi/Nah as Manaketes, Noire as a Sniper/Bow Knight, Sumia/Cordelia as Dark Fliers/Falcon Knights, etc...
That's mainly what I'm going for, which is why I'd like to at least optimize the mother/father pairings - to make up for the sub-optimal classing. And I'm planning on marrying Lucina with a +mag/-def MU.