It is just a matter of time before an experienced business starts up an exchange and gobbles up the majority of business. MtGox and other exchanges may be okay for now, but mainstream customers won't tolerate these "sorta kinda works" businesses. MtGox is going to end up the Avalon of exchanges (delivers, but still can't get itself together quite right). It won't be long until we see an exchange version of ASICminer. A company that takes advantage of a market filled with amateurs.
Absolutely. Although I would prefer a more even distribution of the market share. Ideally no exchange would have more than a 30% of the market share. Exchanges would have a greater incentive to compete on fees, technology platforms, and other features. Perhaps exchanges would be more regionally based as it can be very onerous to comply with all the regulations throughout the world.