Looking at the rest of the list, how on earth do you stop the financial sector from... creating complex products? Derivatives are, at heart, bilateral contracts: how can you ban two consenting adults from entering in to such a contract?
The only bilateral contract is a gentleman's agreement. Binding contracts involve an implicit third party, the state which (through its courts system) stands ready to enforce the terms of private arrangements. The state is not, and cannot be, totally neutral in its role as contract enforcer: Communication between contracting parties is always imperfect; the universe presents an infinite array of unforeseeable possibilities; even very clear contractual terms can be illegal, repugnant, or contrary to the public interest. The state makes affirmative decisions about how it will (or will not) enforce the terms of contracts. Libertarians may have perfect freedom to contract, if their agreements are self-enforcing or voluntarily adhered to. For the rest of us, every contract is a negotiation between three parties, the two who put a signature at the bottom of the document, and the state which will be called upon to give force to the arrangement when disputes arise or someone fails to perform. I think of contract lawyers as two-bit psychics in fancy suits. Much of their job is to channel the voice of the incorporeal Leviathan, so that its quirks and predilections are taken into account whenever agreements are drafted.
This has something to do with derivatives, but even more to do with one of Taleb's broader concerns: debt. At present, the state enforces debt contracts by permitting lenders to force nonperforming borrowers into bankruptcy. That is not a natural or obvious arrangement. Bankruptcy evolved as an improvement over automatic liquidations or men with big necks and brass knuckles. It serves to balance the contractual right of a lender to be timely paid with a broader interest in preserving the overall value of enterprises and preventing extremes of immiseration. To some degree, bankruptcy lets debtors escape the terms of their own agreements and limits the right of contract (though bankruptcy is onerous enough that debtors don't seek this sanctuary easily). The fact that creditors' rights are limited is socially useful: it encourages lenders to discriminate between good borrowers and bad, reducing the frequency with which resources are lent foolishly and then destroyed.
One thing I think that we are learning from the present crisis is that the logic of bankruptcy hasn't been taken far enough. Creditors' rights are too strong. Creditors have insufficient incentive to discriminate, especially when lending to "critical" organizations, because the bankruptcy that would attend a failure to pay is too disruptive and destructive to be permitted by the state. We have seen tremendous resources lent to banks thoughtlessly, and then squandered or stolen rather than carefully invested. Similarly, those who entered into derivative contracts often ignored credit risk when a counterparty was seen as too dangerous to bankrupt. If it were possible for borrowers and counterparties to welsh on their agreements without provoking consequences as disruptive as bankruptcy, creditors would have more reason to be careful of whom they do business with, and potential deadbeats (like large financial firms) might not be able to take levered risks cheaply.
I think that, going forward, the state will have to limit the right of debtors to enforce claims by bankruptcy. Creditors and counterparties who go to the courts would run the risk of having their claims converted into something like cumulative (and maybe convertible) preferred equity. This would ensure that no dividends are paid to stockholders until the disgruntled creditors are made whole, but would not otherwise disrupt the operation of firms or affect other claimants. (Such conversions could be combined with tight compensation limits, to prevent shareholders and managers from taking payouts as wages and bonuses while failing to pay creditors forcibly converted to equity.) Judges would weigh the rights of creditors against the costs to other stakeholders in deciding between formal bankruptcy and ad hoc conversions, so that the risk to creditors would increase with the size and interconnectedness of borrowers.
It may be hopeless to try to control what kind of contracts private parties write amongst themselves. But we can control how contracts are enforced. There is nothing natural or neutral about how we currently enforce debt contracts. We made up some procedures that seemed to work reasonably well. The current crisis has exposed some shortcomings. Nothing prevents us from modifying how we enforce contracts in order to improve the incentives of parties to manage their own risk, and to prevent collateral damage when private contracts come undone.