I'd love to see a Runeterran twist to a medieval aesthetic with Icathia. Jax somewhat resembles a medievalist style especially with his plume, Zilean has clockwork and The Last Light of Icathia has a medieval look to it imo.
Could be some pretty cool stuff. Although for me, I envision Icathia as a pretty progressive society in terms of technology (for that time period in Runeterra) for some reason. Who knows though, Riot can explore a lot of options.