The only reason I bought the iPhone 6 Plus was for the optically stabilized camera. If I could get that in a 4" form factor, I'd be all over it, especially if they made sure to include the new antennas for improved LTE reception.
I'm still traveling with my trusty 2012 MBA. I would love to upgrade, but Retina Display is a requirement for me if I'm going to spend the money. A 15" is very appealing to me, as is the Skylake chip. I look forward to seeing what Apple ships this year.