Yeeezus, the Koke rumours are exciting as hell. Don't think it'll happen though but it would be a dream!
Edit:
I think that he'd want to leave if the right offer came. Barca is still the better club and it seems that Atletico will sell many of their key players to reduce their debt. I can't imagine that they'll have similar success in the next years. Koke is 22 and to play for (arguably) the most pretigious club in the world could be a strong argument for him. Moreover, Xavi's retirement and Cesc's possible departure would almost secure him a place in the starting XI and Barca is able to pay him a higher wage than Atletico.