Very good question. First, I guess, decide if it IS a problem. Then define the problem. I would say the problem is not about the banks it is about the way that greed has become an acceptable (in some quarters) way of life. What would once have been considered an afront to decency has now become just one of the options for getting from birth to death. What was once considered the actions of a psycopath (and then a sociopath) has become a game. These people have realised that there is almost nothing society can do to stop them all, that some of them can and will get away with it and the percentages are worth the risk.
Now, if that is a fairly accurate representation of the situation, we can see that most things will not work. Government legislation will not work. Civil and criminal law will, for the most part, not work. Pleading to their inner sense of decency will not work.
Mmm. What are we left with?
Somehow these people, the white collar criminals of the Enrons, the RSBs the Barclays, the Morgan Stanleys, etc etc must be punished. I would suggest that they be forced to repay every penny of any salary earned during the time of their criminal activity. All bonuses, share entitlements, directors loans and all assets acquired during that time must be forfeited and each of them and every member of their immediate families be reduced to a life in which they cannot earn more than an average worker, no matter what they do, and they should be allowed to live out their lives accordingly.
Any advance on that?