I don’t even know why Apple bothered with the iPhone 6, because it will go the way of the iPhone 5C: a niche product; a consolation prize; the budget choice for Apple loyalists; something you get begrudgingly and regret later. The iPhone 6 Plus is the superior phone.
I've wanted to write this for some time, but hadn't because there was no solid data to back-up my assertions. I do now. This is about why I believe the future of tablets (and by extension, computing) is 15-inches in display size, perhaps even 17-inches.