You won't see 8 core native in non Server parts til HW-E.
HW-E is confirmed 8 core native.
One could hope this means skylake will drop with 6 core mainstream.
But i geuss it depends how much threaded traction the consoles will give.
I have not studied a lot of road maps, but this is just my gut feeling. Especially if amd goes all apu, which looks likely, and tops out at 4 or even 6 cores, giving even more emphasis to jaguar cores as well, I fear Intel will never go to 6 cores mainstream on the desktop.
I would also not be surprised if 8 core has well E is cancelled. But this is just speculation of course. Unless amd brings out 8 core highly improved cpus, I see no need for Intel to bring out a 6 core mainstream CPU. I just see continued emphasis on improved igp unfortunately.