It sucks that a lot of people are having issues with cocoonjs in conjunction with C2 I can sympathize.
Problems like these are almost intrinsic when using multiple software from multiple companies in the same production chain. And it's frustrating, when you can't get info or fixes directly from the source. For whatever reason. Regardless if a person really wishes to solve the problem they need to try a different strategy. This seems to be what you have suggested in other posts with Game closure, and I agree that your onto something. But it's going to take a lot of work on the part of the user to make it happen. Specific questions even if hard to figure out are more likely to get figured out then negative generalizations. But I'm sure you get that.
Check out Game Closure like Ghost mentioned. Users are making good progress with it.
Also try testing your game on mobile devices using a few different browsers and see what kind of performance you get. it may give you insight.
Due to it's tighter limitation it's always going to be harder to pull off on mobile what can be done on less constrained platforms even if it's native.
find and take a look at the games that have been released for mobile with C2 and look for ways you can address performance problems like they have.
Good luck and I hope you find info that will help you.