I think that two exhibition games in a supporting role is rather thin evidence on which to draw such a sweeping conclusion. If you said, "Molly probably isn't quite the athlete that Kelly was, based on the evidence so far", I would have agreed with you.
But I think the earlier comparison to Mel Thomas was more accurate -- less athletic than Kelly but more so than Megan Gardler. I think Molly is probably a better athlete than Mel (based on thin evidence to date): bigger, faster, and seemingly stronger although we haven't really seen anything that would test her rebounding strength yet. If she ends up contributing as much as Mel, she will be an integral part of the team for the next four years.
Remember that Mel was at sea mentally in her freshman year -- the offensive scheme hadn't clicked for her yet. Molly seems to have gotten beyond that obstacle already.