Thanks for opening this thread, seems good to reset the discussion now that the merger is approved. I don't think there are any relevant facts at the moment other than those you stated.
To me these are the relevant points that could help frame the discussion (feel free to add more):

1. What will happen with miles? (e.g. conversion ratio)
2. What will happen with status and status miles (status match, status tiers/dates, lifetime membership)
3. When will Asiana exit Star Alliance?
4. Will there be any changes to Korean Air's mileage program? (e.g. considering that the status tiers between KE and OZ currently only have partial overlap)

What I've heard so far regarding 1. is that the Korean regulators will specifically be paying attention to the conversion rate. The only benchmark I have is credit card programs, where the ratio is OZ 1.5 : KE 1, but I'm hoping in an abundance of caution not to ire the regulators, KE will be more generous than that.
The follow-up question would be 2. what happens to status and status miles, e.g. would OZ Lifetime Diamond + be downgraded if they don't meet the KE ratio? In the same vein, would the ratio be applied to progress towards lifetime status or would the counter even be reset? (this is my greatest fear since I'm over 3/5 of the way towards Lifetime Diamond +).
Regarding 3. Does anyone know precedents from other mergers? It seems likely that Asiana will leave Star Alliance sooner than the 2 year transition period, but I wonder how soon. Lastly 4., KE had some plans to overhaul its mileage program that got scrapped due to regulatory scrutiny. I wonder how much of that will find its way into an overhaul. I can't imagine KE maintaining its current program as is.