I would have Arya feel resentful of her people. She would be upset at how they just closed themselves off from the world when she was captured. Attention would be paid to the flaws of the elves. And the elves eventually sending troops to help would be a result of Eragon. He and Arya would point out how they can't just abandon the rest of the world.

I think this is the first time I have seen an idea that could really help showcase her in a better light.

Arya persuading for her people to help and stop hiding is actually a great characterization for her. It showcases how much she cares for the wellbeing of the world as a whole and how they need to join together to fight for peace. Arya knows that Galbatorix will destroy the elves so they won't have a chance for a future if they don't join the cause now while there is a fighting chance.