If there is a CN ASIC, will the dev core commit to changing the hash, in the case where it is substantially more cost-effective than cpu or gpu mining?
That would be a centralized decision, and by doing so it would greatly undermine the trust people have in the coin. I think it is pretty much impossible for any coin established (except if it's really a matter of life and death, say if the hash function is broken).
For instance Bitcoin would go to less than a $ instantly if a bunch of guys (the devs of bitcoin core) would decide to switch from sha256 to another hash function, no matter the motivations behind.
And if it's not established, well there's no ASIC...
This is a misconception of how p2p coins work. The users and miners have to agree to upgrade, and this is a decentralized, not centralized, decision. They can refuse to upgrade, ignoring the developers. Inevitably new developers would come forward to take over maintaining and developing the old fork, as has happened countless times in open source when the original developers made some decision not supported by a significant portion of the user base.
With bitcoin it is much too late, because the miners already have hundreds of millions of dollars invested in ASICs and the users simply want security and stability so they would likely stay with the miners. The devs' fork by adopted by no one and would die.
But this is not necessarily true for a coin if the change were made before a large investment were made in ASICs. In fact miners might well prefer not being arms-raced into giving money to ASIC developers for no real gain to themselves and support the fork. Users would likely support it as well, since ASICs would lead to increased centralization and many users are likely also small scale miners (especially for a coin where CPU mining remains viable, as with this one).
Furthermore if the decision is made ahead of time, or even just left open as an option ahead of time, there is no loss of trust, because there was no commitment to not change, and therefore no breach of trust. While there is no stated commitment on the part of the developers of this coin to change the PoW for any particular reason, changes have been considered. At one point there was thought given to throwing out CryptoNight and replacing it with one of the functions in widespread use (but of course keeping the rest of the cryptonote functionality such as ring signatures, etc. -- the two are in fact not linked at all).
There is no change under consideration at the present time, but don't count on there never being a change.