I just don't know if its down to Martinez the last two seasons, for me its hard to think its purely down to that because Martinez was his mentor and he would always play for him.
The MF set up at the moment is too defensive, we need someone who is a playmaker and a enforcer. Mascherano and Alonso like. Right now, i haven't seen enough to convince me that McCarthy is disciplined enough to do that job, and i just don't think he has enough to his game to be the playmaker - but thats not his game so we shouldn't expect it.
If he can get back to the high energy pressing game, and tidy up parts of his game which i see as rough, then he could do it. I do think there could be better options out there - but who knows Koeman might love him there, might hate him and go balls out for someone he wants.