Deep doesn't mean everyone can score, but everyone can contribute at least. For most of the conference season besides garbage time in the last few minutes of blowouts, the only significant minutes have been played by 7 guys and Eastman for a few. Look at the box scores. Against Creighton we played 8 guys total and Eastman only played 5 minutes. I know McCain has been hurt, but even when he has been available he hasn't played that much. Our starters play well over 30 minutes with SS spelling WE and DSE spelling the guards with a few minutes from JE. Even when McCain is healthy, when is the last time we played 9-10 guys significantly? We have used 8 guys a lot lately, so I would say we do not usually use 9 guys very regularly.
A team that has 7-8 guys that play significant minutes is not a team I would call deep. I think we have a lot of potential to be deep in the future, but for whatever reason most of the guys on our bench are obviously not ready yet or they would be playing. Injuries have had an effect as well.