There are at least 4 choices that can be made in the event of a hardfork between competing chains -
1) Quickly move over to the longest chain with the most hashing power out of security fears
2) Stay on their chain with less hashing power and hope...
[snip]
You can stop at 2, as the other 'options' are just slash and burn/scorched earth policies that will end badly for those foolhardy enough to believe in them. Most rational players will want to conserve whatever value they have put into bitcoin and are unlikely to be as petulant as the core devs will be. They will follow the longest valid chain.
Changing the POW is just empty sabre rattling from a dev who is seriously worried that this is getting away from him.