No doubt the major investment houses will be leaner and meaner. But Congress needs to set the rules. That means controlling the Federal Reserve Banking system and setting minimum requirements for mortgage loans by investment houses. This wil be unpopular with two groups. 1. Those opposed to any regulation and 2. Those who want even the marginal applicants to buy homes.
Will the elected legislators be up to the task? The guy (or gal) at the top can only propose and recommend, and at the end sign or veto, but unless the legislators agree, little will change. (Of course one obstacle will be gone; Bush would probably veto any serious attempts to change the rules if he was still in the White House).
In other words, serious change depends on electing a majority of much more economics-savvy congress men and -women. This is a tall order.