I don't think the prices will change, as the market all of a sudden will not be willing to pay non stop prices for indirect itineraries with stopovers. What will change is those who do ex EU's will be able to drop the last segment without fear.

Or perhaps the pricing will change, much like the domestic market changed in Canada when LCC's came in. It used to be that there was restrictions that all journeys were returns and had Saturday night stay requirements, or one ways were much more expensive, much like trans atlantic one way flights are now. Then the LCC's introduced segment pricing, and now all domestics are segment prices - a return is 2 one ways put together. Makes open jaws much easier too. I could see the legacies doing long haul flights that way too eventually.