[Mithalwen]

Certainly her horizons widened but I think that is a little harsh. Eowyn is at least a quarter Gondorian through her grandmother Morwen of Lossarnach - who despite her name was of the strong and noble Numenorean line of the Princes of Dol Amroth. Faramir and Eowyn are cousins (albeit third or forth cousins). But on a more general level I think the two countries will be brought closer in many regards by the intermarriage of their noblest houses (with Eomer and Lothiriel also). Gondor has culture, but Rohan has perhaps more vigour and dynamism.