If Hourihane wants to leave, I believe we should let him go for quite the low fee. He deserves that, and he has fallen down the pecking order to be behind Nakamba and Ramsey as well.
I like Hourihane, but he is not suited to how we have evolved into playing now. As others has said, I believe he would be good in Newcastle, Burnley or WBA, teams that play a style where he could thrive more.
Hope all Villa fans can see that he has contributed alot during his time, scored some great (and important!) goals for us, and if/when he leaves pay him the respect he deserves.