First off, the Razor Core has an integrated gpu as well, so that's still not a good fit for someone who wants to play a fairly demanding current game.
Razer Core is the housing, where you can put a desktop GPU in.
Razer Stealth is the thing you might be thinking about. Integrated GPU only on the U-series processor. ITs an Iris 520 at that, if I'm not mistaken.
The Razer Blade 14 has a GTX 1060 tho. And it's not a thick nor heavy laptop. I'd like to see what a GTX 1050 will be, and if it would fit the Mac's...
Anyways I still believe that the Mac 15'' will either have only an Iris 580 or an AMD solution. This whole Nvidia noise that's going around must be for an external solution, maybe Apple comes out with their own thing and say "AMD cards support this and we are hard at work with Nvidia so their cards work as well in the near future".
If Apple doesn't care for an eGPU option at least make it so as the Mac's support the Razer Core via Windows 10 Bootcamp... Would be better than nothing.