Apple has a tragic record with portable Mac`s with dGPU; As long Apple continues to run high power components at their upper limits for the sake of form of function, the potential for premature failure will remain. Personally I now avoid portable Mac`s with dGPU, as in general they simply run too hot, which can and does result in failure, increased fan noise, and or throttling. If I needed a notebook with dGPU, I would be looking at a Windows based system, not Apple. Opting for a portable Mac with dGPU is little too much like "rolling the dice" for my liking.
Apple`s strategy remains the same "thinner & lighter" at all costs, therefore its`s safe to assume that Apple will push the thermal boundaries of the upcoming 2016 MBP. I rely on my Mac`s for my living, my first consideration is reliability, thankfully dGPU is not a requirement. There`s good reason why Windows OEM counterparts have significantly greater ventilation, nor is it related to the designers and engineers abilities.
If you need the dGPU then options are clear, if you don't need the dGPU it`s best avoided, as it`s simply a weak point in the chain, especially with the MBP.
Q-6