I'm thinking some very likely acts (not necessarilly headlining) are Nick Mulvey, The Vaccines, Nation Of Language, Everything Everything, Baby Queen, Jockstrap, Big Moon and potentially Django Django. Of course, a dream list, but with touring next year, it'd make sense.
Dream acts would be Bombay Bicycle Club, Aurora, MGMT, King Gizzard And The Lizard Wizard, Sigur Ros, Years & Years, The Jesus And Mary Chain, Oliver Sim (I've wanted to see him live for ages), Romy and Jamie xx.