I doubt it would be a defense argument (reactive, implying an appeal), but it's definitely part of a defense strategy (proactive). Jury consultants, or at least the ones I've watched on cable TV over the last 26 years, would likely disagree with you about what a potential jury will be influenced by, either consciously or subconsciously.
I'd be interested in hearing from one of our current or former attorneys on this.
I think the defense will want to do what they can to help humanize her and make her more relatable, so that if by chance they're able to throw some FUD (fear, uncertainty and doubt) at the prosecution's case, that her seeming more like the average "soccer mom" will make it even a little bit harder for a jury member to vote for a guilty verdict (on some or all charges).