There is a good argument that there are soundness and efficiency gains to be made by requiring banks to hold more capital – within reason. More capital would help deliver both greater certainty, and higher expected output (before and after a crisis).
This is illustrated by figure 5, where the level of financial stability is measured on the X axis and the expected output is measured on the Y axis. At some point more certainty comes at a cost, though this may be justifiable if we desire greater certainty.