I don't think mobile parts belong in a desktop workstation to begin with, to be quite frank. The reason you use a desktop in this day and age is because you want power, more than even the beefiest of laptops can hope to muster. That goes for CPUs and GPUs alike. Otherwise, why stick to one space if a laptop/tablet is good enough? Then again, I was never a fan of iMacs and other all-in-one desktop systems with no expandability to speak of, particularly because Thunderbolt 3.0 is a very recent thing, external PCIe docks are still very expensive (and limited to the PCIe 3.0 x4 bandwidth that TB 3.0 provides), and on top of all that, external GPUs don't help with built-in displays all that much.