Westwood isn't the problem, the fact that he has been good enough to be a regular starter for the last three years is the problem.
I think he is a decent enough squad player, and for £1m that is a bargain, a success. Worse players like Sylla, Tonev, Bowery etc weren't the problem, because they really weren't good enough so we just got rid. Westwood has been good enough, and that is the problem that hasn't been fixed for three years.