The problem with processors like bitpay is two-fold. First and foremost it's a third party risk as to the exchange rate fluctuations. By that I mean that this is a volatile market if I take a bicoin payment and the price drops 30% in a day I would potentially lose all my profits on items sold that day as the third party processor exchanged my payments for later deposit into my fiat account. Worse yet there is the chance that a processor could use their capital to "float" the payment to me at a lower exchange rate holding on to my bitcoins untill the market corrected and making a profit at my expense. Next there is the fact that avoiding processor fees is the whole reason to switch to bitcoin in the first place. If Visa and MC charge 2.5 to 4.5 percent depending on the card and the transaction and bitpay charges .99 as it's lowest rate what has the merchant really gained by switching? At that point his only gain is avoiding chargebacks from contested charges and fraud.
When I say the market needs the ability to transfer payments instantly I mean that I need to be able to (if I choose) transfer the overhead portion of my bitcoin income into fiat in my bank account at the exact rate I accepted it at. In other words John Q buys a desktop computer from me for 12 bitcoins and the exchange rate is $100 per at the moment of the sale I need to be able to rout his payment to my exchange account sell the 7 or 8 bitcoins to cover my expenses and have that money in an account that I can make payment to my supplier within the hour. I would want to have complete control of the remaining bitcoins that were my profit so that I could choose to liquidate them or save them for a better exchange rate. This type of control without a third party is the only way small businesses will see the upside.
As to the assumption that stop-loss orders firing automaticly would have made the crash worse than it was I think you're forgetting the fear factor. People don't panic if they know they will be able to sell their bitcoins at the rate they want to (or at least close to it, I'm sure there would have been some slippage) The reason for the crash was panic due to falling prices and more than a minute of lag all day. You have to remember the herd mentality of an exchange. One person getting scared and clamoring to sell will only spook the other investors if they are: 1) already afraid 2) convinced this person knows more than they do 3) fearful they won't be able to place their trade at their risk tolerance level once the frenzy starts. If you have a stop-loss set up you don't have to panic, if no one has to panic, the market doesn't have a panic-driven rush to sell.