100% NACK from my part, I've already mentioned it in another thread.

I welcome the addition of post-quantum schemes as soon as there's a battle tested and future-proof option available. But it does not make sense to make the usage of PQ cryptography mandatory, and much less from phase A on. The PQ option should be optional at least until there are already ongoing attacks.

If 25% of the coins are vulnerable, what has to be done is to educate people that they should not re-use addresses. Satoshi's coins and other "lost coins" where this is perhaps not possible are only 5%. And these 5% won't be cracked instantly by quantum computing, it will take time. So it's not that we'll have 1 million BTC of new market orders on exchanges in one single day (which could be disruptive).

In our chainanalysis-plagued world it is even possible that the quantum hackers would have a difficult time sending these coins to CEX exchanges. They would have to sell them via P2P or OTC for a much lower price probably. Of course there could be a disruption due to panic, but once the coins are sold or exchanged for goods, the threat is gone forever, and there will be no more "Satoshi's Coins Are Moved!!!! FUD".