I think my previous idea that the GoKaigers would have something to learn from their predecessors is not really the case. It seems more that the previous heroes are doubtful of their ability or their motives especially since they are pirates looking for treasure that don't seem to really give a damn about protecting Earth. They remain skeptical until they are otherwise convinced they have some quality about them that makes them worthy of the powers.
In this case it would seem to be the trust they have in one another. Which may be a call back to the realization that Kaoru had in Shinkenger that though she is the real ShinkenRed, Takeru is who the group had fought and suffered with so their hearts and loyalty were to him despite the fact that they respected her authority.
I got the impression the whole reason she wanted to basically observe the group is because she was looking to see if some quality like that existed within this team.