It'll be interesting to see if they believe in the MB enough to pull the plug on the MBA. The overall consumer response has seemed to be lukewarm compared to the loved MBA. It didn't seem an evolution as much as a compromise device. It seems like minor chassis modifications to the MBA chassis and the same screen would have breathed new life into the MBA (which was doing just fine) - but instead they created a whole new product that as a whole didn't seem as good. But if they stubbornly stick to the current MacBook design and pull the Air, there is no question I'm snagging a MBA before they are gone and calling it a day. All of their insistence on a single port.
Sort of like I have a bad feeling I'll be grabbing a 6s if the rumors of the headphone jack being removed from the 7 are true. Taking away functionality to make things more complicated is the exact opposite of the simplicity that makes Apple great.
If we thought Apple was "locking people in" in the past, it is only going to get worse.
You might want to grab a 2012 cMBP i7 for later eBay resale. The last upgradeable MBP. Or indeed the MBA you suggested.
The screen on the rMB might be great, but the new keyboard is not, as is the "outboarding" of legacy connectors via a USB-C hub.
The iPhone 7 will probably have a separate dongle for $35 to connect your "legacy" headphone jacks to, else you need to buy their new Beats ones.