Some of what they did seems reasonably clear to me, and is stuff that we have seen before.
Current:
1) Remove the legacy Macbook Pro 13" with optical drive. Simflify line-up.
2) Remove the Macbook Air 11". Simplify line-up.
3) Leave the Macbook Air 13" unchanged, with one (perhaps two) more years. Just for Apple and purchaser cost reasons.
4) Earlier in the year, upgrade to then current Intel Core M line-up, Intel rebranding for the higher bin parts notwithstanding.
5) Introduce new 13" and 15" Pro machines, with new feature set, including Touch Bar and four TB3 ports.
6) Solely because of the current cost deltas between #3 and #4/#5, introduce a deviation without a second Alpine Ridge controller/TB3 ports, Touch Bar, and slower cpu. No major re-engineering effort needed, and only has to last a year (or two at most) in the line-up.
Next year (or the year after):
7) Macbook Air 13" is removed, officially.
8) Cost of Core M parts is lower, and Kaby Lake means more port options. So swap port for TB3, and maybe a second port. Instead of $1300 being the entry point, you can lower it to $1100 or $1200. Maybe have only the 12" model, but equally possibly introduce a 13" model. Still essentially the same internals just bigger battery and screen.
9) "Gimped" new Macbook Pro 13" with regular function keys is removed from the line-up.
10) Keep iterating on 13" and 15" Pro line with Touch Bar. Add 32GB ram as an option when they move to Kaby Lake quad core parts on the 15", with LDDR4. Slightly reduce them in price over time.
This all makes perfect sense to me. #6 is just an abberation/stop-gap mostly because of pricing. The Macbook Air's path from high price, newer tech, lower size, and reduced functionality . . . to what is the current Macbook Air which is a pretty good value still, excepting the screen should give us all the clues necessary. It just feels a little bad right now to have to pay what we have to pay for "current Apple tech". I think the "Macbook" and "Macbook Pro" chassis are essentially what we are going to have for the next four our five years, and the legacy stuff and "bridge" will be gone within two years.