I'm not sure where you're coming from with #2. Most exchanges use price-time priority to determine execution order. From the description the best bid was $0.01, so obviously he would get filled first at $0.0101.
The real problem is that the market was able to descend to that level to begin with. There should have been some sort of circuit breaker limits in the Mt. Gox system that would have halted such a massive decline, similar to what exist in the US equity and futures markets.
As to #3, really the only thing that matters in terms of exchange access in the US is that you satisfy the appropriate compliance burdens (broker-dealer status) and can pay the fees required for naked access. That may be good selection criteria for "informed traders" but it certainly isn't any guarantee.
What I meant in #2 was that there are market structure rules about things like minimum price improvement levels and how widely a buy or sell order is circulated before finding a cross. The HFT guys are masters at exploiting the market microstructure to extract alpha. Google SOES bandit if you need further examples.
As for #3, naked access is a relatively new invention and the rules are sufficiently constructed to virtually guarantee that only implicitly informed parties are ever going to see "naked" access.
Circuit breakers (actually the lack of them) is one of those things that enabled this to occur. The party in question essentially copied a strategy that was used by the HFT guys to soak up the offer. The seller got liquidity but it came at a very dear price.
And that's really the issue here: circuit breakers are a compromise between liquidity and price discovery. If the exchange suddenly sees that price discovery is trending outside of a range, they shut down trading. If the problem is a systemic market one, then this probably is a good idea. But if price movement is because of new information, then all the circuit breakers in the world wont help you because as soon as trading resumes, the new regime will be in play.
An order with 1/100th penny precision isn't usual for currencies, but I see your point. Either way, this was a very unusual situation. Why were there so many people sitting at $0.01? If you're going to play that game, why not jump on at $0.011 or $0.02? Hell, pretty much anything < $1.00 you could probably safely assume would give you a profit as long as you were willing to bet you weren't watching the demise of the BTC.
The real problem is that the market was able to descend to that level to begin with. There should have been some sort of circuit breaker limits in the Mt. Gox system that would have halted such a massive decline, similar to what exist in the US equity and futures markets.
As to #3, really the only thing that matters in terms of exchange access in the US is that you satisfy the appropriate compliance burdens (broker-dealer status) and can pay the fees required for naked access. That may be good selection criteria for "informed traders" but it certainly isn't any guarantee.