Thank you for writing this up!
In my opinion, the discussions of ProgPOW and ASICs among the core developers has been suffering from the lack of expertise in modern hardware manufacturing. Core Devs do not have internal hardware experts, as far as I can see. I have asked (though not publicly) for a commissioned research/analysis into the issue of ASICs and its impact on the Ethereum network, because I saw this was the only way to bring that missing expertise to the table. But alas this idea did not get traction at the time.
As far as I can see the main worry that people seem to have with ASIC is what you described in item 2:
Item 1 on its own is not a reason for concern:
But even if the secretive mining is occurring at the moment, it only poses a problem if it occurs over the long time horizon. If it feasible that there is a real competition coming from ASIC manufacturers who sell their devices publicly at fair price, and they can catch up quickly enough, I do not see the problem with temporary private mining - it will be a minor blip in the history. My main question to an expert is this: how quickly can competing ASIC manufacturers nullify any advantage that another (possibly bigger, like Bitmain) manufacturer has? If the answer is less than a year, then I would say, definitely not to bother with ProgPOW, and just leave things are they are.
My main concern with ProgPOW roll-out is that it is a distraction from scalability track, but I simply lack any credible information to convince people to not do it, or convince myself that it needs to be done. The reason I suggested that the decision about ProgPOW was to be made yesterday is based on my assumption, that no new information will come to light for the next 2 weeks, and so we will keep procrastinating. On the other hand, making a tentative decision produced a good response that we needed - people started to take the issue seriously enough to start talking.