What Is Greg Walker’s Job?

This post refers to southsidesox.com

Jim Margalus of South Side Sox on Greg Walker:

Plus, there’s only so much a hitting coach can do (as Carlton Fisk told us), and if they made a bigger impact, they’d be paid more.

What? What kind of excuse is this? If the hitting coach doesn’t do anything, they why have one at all? Don Cooper certainly seems to do something. Shouldn’t it be Walker’s job to make adjustments and recommendations for improvement? Adam Dunn has hit over 350 home runs. You don’t do that by accident. There is clearly something wrong. If it’s not Walker’s job to fix that, then who’s job is it? And what does Walker do?