I think that clinging to the immutability ideology is going to doom ETC from the start. All block chains fork. Many have forked to undo and even reverse vulnerabilities. If ETC is to survive, it will probably have to fork as well sooner or later. To not consider this possibility is to ignore that blockchains exist in a larger economy that must interface with the human world.
In addition to inflexibility, ETC also suffers from having no clear development roadmap or dev team. If the plan is to mirror commits to ETH as best it can, then there will come a day when merging these commits won't be compatible with immutability. At that point, it will become obvious that ETC is either a coin that merely makes a statement or a stunt to make someone some quick BTC.
there are two approaches to forking: one is where you have as close to 100% consensus as possible, and a bad one.