I believe that looking at the bounded AUC or at the steepness of the ROC curve is equivalent.
For example, in medical diagnosis, you want a steep ROC curve because you want the False Positive Rate (FPR) to be very low for a reasonably high True Positive Rate (TPR), e.g. you don't want to proceed with treatment for healthy patients.
In this case, if you were to choose a model with a steep ROC curve it would be equivalent to choosing a model with a high AUC in a bounded region near the origin.
Assuming that the ROC curve in the bounded region is approximately a line ($y=m x + b$), the area under the curve would be proportional to the slope of the line ($area=m$). Therefore the model with the steepest ROC curve and the model with the highest bounded AUC would be the same model.