My game probably isn't "huge" when it comes to logic (it's a sidescrolling horror-survival game) but it uses quite a lot of effects and animations and so far i haven't had any issues previewing in NW.js... And C2 never crashed on me once.
My perspective is this: i see these kind of performance posts and threads pop up all the time and it made me doubt my engine of choice in the past but first, as i said, i've never experienced any difficulties so far and second: I'm not a coder. I've tried my hand at many game creation software, a lot of them who are being discussed on here regularly. I always returned to C2, because it's the only package where i got the results i wanted and which has the most intuitive UI in my opinion (i'm not just talking about the Event Editor but about the UI in general).
So i had two options: either make my game using software that i feel comfortable with and end up with SOMETHING in the end, maybe risking some headaches when it comes to performance or whatever OR go with a software that i don't even like and, probably, give up in the end because i'm too simple-minded to use it and have no game done.
Easy choice for me. No engine is perfect. Often times you trade ease of use for features and vice versa. But if you browse any forum, GameMaker, Unity, Stencyl etc., you'll see that there are always complaints by the users. So yeah, if you still want some flexibility in your game and not just some templates where you can paste your own graphics in, it really doesn't get much easier to achieve your dream than C2.