I agree on a “clearing house” approach and more up front cash requirements for derivative type investment instruments created by, offered by, or bought and held by a financial institution, but ONLY if that institution is a government institution (like a government pension fund) or has some sort of government guarantee on some portion of it’s assets (like a bank with FDIC deposits). The rest can do want they want, and if they fail then their assets (what’s left) and their customers, will readily be picked up by someone else.
India, China and Canada’s banks escape the meltdown simply by not allowing derivatives. Keep it simple, let Wall Street have some leeway and they will screw the country again with the same instrument.