It's creating a "second instamine" where the PoW rules are changed in secret, the secret is revealed like a few hours before the PoW-change block, and as a result the only people who can develop miners that actually work on launch day are the insiders.
I'm also a bit worried about miner availability upon algo change. However, I expect the internal CPU miner of the daemon to work. After all, it will have the correct algo for verifying blocks. In fact, that might make things interesting again, just like the old times of Bitcoin in 2009-2010 before external miners.