Haha!
I think we both can agree on that the cards ain't gonna survive on one fan only. To make the design depend on one fan to take 80% of the total needed dissipation isn't sound either. Makes for a too loud of a card. The best offload sound wise would be for the both fans to dissipate heat evenly. That's the dream scenario. My guess is that the back fan isn't doing quite as much as the "front"fan, to dissipate heat from the fins, but does a great job not circulating heat inside the case. It would just be asinine to put a fan on that realestate if it stood for 30% total cooling capacity or less.
Not at all, it can provide necessary cooling even if it's not moving a large portion of the heat. There's a lot of components in that front part of the card that require cooling, like the VRMs, inductors and RAM. Using a full coverage plate that ties into the main cooler is one way, but another is just to run air over them. An extreme example of something like this is cooling a card using something like a Kraken G10 bracket or one of the factory hybrid coolers. The vast majority of the cooling there is provided by the water cooling radiator, but the board still needs active airflow.
I disagree that the best arrangement soundwise is to have both fans dissipate heat evenly. Take a look at the cooler.
The front fins are tied into the vapour chamber, but the stack height is much smaller than the rear fan. Even if the airflow wasn't obstructed by the PCB, you would need greater airflow to provide the same cooling through the front fin array, which means more RPM and thus more noise. The airflow is obstructed by the PCB and the shroud though, and has to take a hard 90 and travel in that thin stack between the fan and the board, along all the high z-height components, and the up and around the HDMI ports and out the back. If you tried to provide equal cooling, the exhaust air will be a loud, high velocity turbulent mess and the fan will be spinning like a banshee trying to force it all through while the back fan spins slow and easy. The best compromise for low acoustics would be to have both fans run in a way that produces the same amount of noise, as long as thermal constraints on all the subsystems are met.
Really, this is an example of the entire reason people water cool and use big tower heatsinks on their CPUs. You take the high density heat and rather than try and deal with it in a compromised location, you use a high efficiency transport to bring it somewhere where you can use a nice big lowish density fin stack and a big fan to send low velocity laminar airflow through it. Low noise, good cooling.
So, back on track, AMD doesn't need a shrouded rear-exhaust card with axial fans, and I'm not really sure it's in their best interests to hire you as their thermal design engineering lead.