Most egpu solutions that are on the way are either proprietary or at least require some small tinkering from the computer manufacturer in order to work. So the situation seems to be that if Apple for some reason does not want a 3rd party tb3 egpu box to work, then it simply will not. At least without hacking or cramped experience (no hotplug etc.). And the Apple's moneymaking possibilities for making an own egpu box or settling a deal with 3rd party producer are good. It may not be big money but takes only small effort, margins are good and such box can be sold for iMac and maybe MacMini users as well.
Unlike before, the current top igpu (Iris 580 Pro) seems to be so good that better performance would only be required for gaming, video editing, 3d, VR and maybe some smaller niches. MBPs are mostly sold for slightly lighter work (photography, design, audio, dev, showing off in Starbucks etc.). Apple is not interested on gamers, at least on OSX. Video editing and cad/3d work is not something that users do on the go that much and those people have used to plug external hard drives and carry all kinds of gadgets anyway. Also VR currently and in near future needs more than just a laptop or discreet glasses to work. So having an egpu would not be that big a deal for those on the need of more graphics processing power than igpu can offer. For them the possible dgpu might still be not enough.
My point is that it might be best_for_Apple to keep their lineup slim and focus on making the laptops slimmer and making small, but easy money with egpu boxes on the side. Of that few, most would still think that the dgpu Apple is offering is not enough and rather have an egpu box instead. I personally don't mind about the size that much and I hope that there will be dgpu option.
So my official guess for the high end MBP are:
- Iris 580 and no option for dgpu
- Apple will use Skylake Xeon processors, since the price is about the same as for i7, but they have more "Pro" credibility in it and make the comparison between PC offerings and Mac more difficult.
- 2xUSB-C/TB3, Audio and SD stays. Hopefully HDMI and one old style usb as well.
- magsafe stays or they will have similar safety detach one way or another.
- thinner bezel = 16" screen or smaller dimensions than previously. I hope for the former but would bet for the latter.
- Apple's own egpu unit sold separately, comes bundled with a AMD Polaris (maybe 1-3 options). Or they have a deal with AMD having the egpu unit that will only work with a very limited selection of gpus. I would bet the latter, since egpu is a nerdy techy stuff and Apple may not want to have their skin tarnished with such.
P.S. Competitors are pushing VR and Apple is looking quite uninnovative in every other field as well, unless they come out with something big. iDevices are not enough by themselves to fool people think they are somehow special if they have one. In the long run Apple needs all the creative people that use the Macs for maintaining their brand, even if the Macs form just a small portion of the sales. All Apple computers are in need of a refresh simultaneously. Maybe there is something big coming?
