Even if the new Mistral uses check valves in the mouthpiece it will still require some slightly different non industry standard techniques in operation and will remove the option in most cases of donating the primary regulator to an OOA diver. The fact that it is "different", "not an industry standard" and based on "old" or even "antiquated" technology that has long since been replaced by "better" single hose technology is problematic from a liability standpoint. It pretty much ensures that some moron will do something stupid with one or use it without adequate training and kill themselves as then of course some laywer will takwe the case and sue the company for selling a sub standard product that allowed the moron to kill himself.
I recently finished "Fatal Depth" and while it is not the best read I have seen on diving, it provides a good example of this phenomenon. A tech diver who lied to his instructor and several other people, wrote an inflated number of dives on the paperwork to qualify for trimix training, and signed a hold harmless waiver to dive on the Andrea Doria, got himself killed on the wreck.
An attorney then represented the deceased family and sued the boat owner, the instructor and the training agency for $36 million dollars because he felt someone should be held accountable. The defendents ultimately won the case but they still incurred substantial legal expenses in a case where the deceased was the person ultimately responsible for the events and decisions leading to his death and had willingly signed several waivers along the way indicating he knew and accepted the risks.
As long as we continue to devalue the concept of personal responsibility and allow trial attorneys to bring nuisance lawsuits we are not going to have an environment that is conducive to allowing companies to do something different. The sad part is that the ultimate cost is borne by the consumer who indirectly pays for the outrageous cost of liability insurance premiums and/or settlements on outrageous lawsuits.