Say a coin running on ETH has a change of mind or ETH crashes and burns how easy is that particular coin to pick up ETC and continue? or will the whole ICO market of 2017 crash and burn with ETH. I do not trust ETH with the security issues and krypto kitties debacle this whole thing will come crashing down hard many will loose much.
Running contracts works the same on both. Transitioning is technically feasible though would require some work.
Of course the biggest hurdle is that ICOs crashing creates issues way bigger than any technical challenge of migrating to a new network.