Secondly - Bitcoin is supposed to be decentralised. If we cannot allow parts of the Bitcoin ecosystem to die off, we cannot make that claim. We should let MtGox die and use this as proof that the network, the community, the technology is decentralised and resilient.
Opting for the "too important to fail" position dramatically weakens the evolutionary process of Bitcoin services. It should fail, and fail fast. This is the market in operation.
Mark would not be involved with this new exchange. In fact this is an opportunity to build the first truly safe and transparent exchange. You are opposed to the chance to build an exchange led by thousands of users. This venture could set an example for all other exchanges who otherwise could turn up one day bankrupt.