Mmmmm... It depends on what kind of quality you want in your depth... If you already have a solid rotation and then you hire a guy like Saunders, He could initially take a depth position and then... who knows? he could take a spot in the rotation whether someone gets an injury or underperform. With him, your rotation would look like very similar. With Cook is a different story; he is a long shot. Last year our "pitching depth" was horrible. This year with all those signings, our depth is not encouraging again, regardless still, the #4 and #5 spots are a question mark. I think that it is the point of the discussion.
IMO the depth should be build mostly with your farm rather than crappy pitchers. Doubrount and Wilson should be part of our pitching depth. The problem is that our pitching in the farm is not enough/ready.