Heh, I also took skills that increased experience, both in the skill tree and in the dynasty bonuses, at first. But after playing a third map, I realized that it's like a fifth leg for a dog.
Experience grows perfectly well anyway.
Yeah, considering the development cap, which is reached within half a mission, this is a very useless skill. Although, all the bonuses for the dynasty are like that, unfortunately:(
and Arachne is a sword, and Nastya won't be able to wield it.