I see your point. I had forgotten about that because AP2 turned out to be a downgrade from AP1 for at least a couple years. Also, being a person who doesn't care much about AP except for stop and go highway traffic, which AP1 does well, I would not have been upset to miss AP2 even if it did work. And I'm not sure about this but I think the AP2 timing was forced by the messy divorce from Mobileye and might not reflect rational product cycle planning by Tesla.
My comment was also colored by the fact that when I decided to buy an MS at the beginning of 2014 I decided to wait until they introduced a large enough update to give me comfort that they wouldn't deliver a further significant update after I bought. For me that update was dual-motor and the P85D: a driveline update, just like what is contemplated now. I recall that AP1 was announced around the same time, although I think it had already been shipping for a few months. Because of next generation seat availability I didn't take delivery until March 2015. Tesla did introduce Ludicrous not long thereafter, but they made P85D buyers whole by offering a retrofit (which I took) which showed they do care at least a little bit about not upsetting those who bought the first update. They introduced the refreshed exterior in early 16 as you said, but by that point the P85D was a year and a half old and I was frankly glad to have missed the exterior refresh! -- it's entirely a matter of my personal taste, but I like the old nose better.
If I were to buy the refreshed driveline, assuming it is in fact about to be released, and they followed it with a pleasing exterior refresh or a substantial interior refresh six months later I would be upset. However, I would bet against this happening because Tesla did wait a year and a half between the P85D driveline and the new nose, and because I would think that given the internal design changes needed for the new driveline and potential battery pack (cooling) changes it would make sense for them to do any interior reconfiguration at the same time. If no interior changes were introduced with the new driveline I would still feel good about making the bet that I was buying right after a significant update not before (hence my comments in the post above). In fact I am actually not planning to buy since I'm still very happy with my P85D. My personal plan is to wait until an exterior redesign in a couple/few years, or until the reliability of my car goes south.