To be honest, I find this a really clever strategy, since you can just drop a product line (with support and development) and focus completely on the new line, the same is valid for the Naza vs Naza V2. Even they can sell of their stock (WKM-IOSD-BT-LED-Waypoint-bundle, Naza Light) without any extra effort. I am pretty sure that there will be no more FW-updates to WKM and Naza-light after A2 is out. "Premium users" will move on the the "flag-ship", as the want the "best" solution for their "big birds". You also have to consider, that the WKM is less than 2 years out, the Naza even shorter, so that is a product lifetime-cycle already close to smartphones.
What I do not get is, why still the Motor-out-ports still have S,+,- as S only would be sufficient (and they could save a lot of pins), even on the RC-Side one +.- would be enough, not needed for every channel, so the main unit would be able to become much smaller. Groundloops (as they are now present on every connected ESC, and on every connected channel would be avoided completely.
I think the reason for all this is the S800, which was a "challenge" right from the start, but instead of correcting the copter, they brought out a IMU V2, and to complete this, plus the point that most "big birds" are octos" they completed the new IMU to a "new" FC. That the GPS/Mag gets bigger is also not a surprise.
Since people always want to have the newest toys, it for sure will be a success.
best regards
Ferdinand