Something like this should "just work" since it only has one purpose in life. It's only reason to exist is to take what we've done and "make it go" on mobile devices. If any single setting or object could make the frame rate drop 30+ frame per second, then that is considered a flaw in my mind.
Clearly CocoonJS isn't fully cross-platform ready, at least not when used with Construct 2.
Hopefully Ludei will sound off on this issue at some point. At least acknowledge it is an issue.
It should "just work"? Do you even have any idea how difficult it is to make a functioning wrapper that effectively "translates" HTML5 into as close to native language as possible?
Ludei, a dedicated team of professionals are working ONLY with that and even they are having trouble with it.
Do you also realize it's completely FREE right now and that you don't pay ANYTHING to use it?
The text object could make the fps drop down 30fps, because of WebGL. It's just how WebGL works, it's not a problem with CocoonJS and it would work just as bad on any platform/combination.
Ludei know of all the issues, a lot of us are giving them feedback and bug reports and they're even visiting the forums from time to time.
You are honestly in no position whatsoever to criticize Ludei for all the FREE amazing work they're doing for the entire HTML5 community.