Agree with you that it looks tough now for Walker to break into the side. That is due as much as anything to their apparent preference for two talls rather than three, IMO. Three talls is quite an orthodox modern forward setup yet we seem uninterested in trying it. I'm not sure why.
Because of one thing; what happens when the ball hits the ground.
There are a lot of people in football now, both fans on here and the media, who repeat the same things over and over, almost like it's going to make it more true. If you are going to play three genuine tall forwards, then at least one of them needs to be really agile. Not 'agile for big man' either; genuinely quick at ground level. None of Hawkins, Clark or Walker are this. Watch how efficiently any defense mops up when the ball hits the ground, and then remember Hawthorn is even better again. That's why.