Personally, I use C2 for making little HTML5 games (portfolio: http://td2tl.com) for publishers. I build my business from nothing but I bought a small apartment last year and I'm still going to college ( I should be graduated like 2 years ago lol ) . Without C2 I couldn't do anything. I've tried most of the engines, there is nothing like C2's HTML5 export and Event System. I will definitely subscribe to C3.
But people are right, because of the export options, there isn't a killer game made with C2. We have good games like Airscape, The Next Penelope, There Is No Game etc. but we don't have games like http://www.yoyogames.com/showcase or https://unity3d.com/showcase/gallery. Most of the serious developers that were using C2 change their engines and C2 remains as a prototype tool. For example, Ori and the Blind Forest and Iconoclasts were Construct games once.
I don't think people's performance problems would be solved by native exporters but the real problem is the 3rd party dependency. HTML5 exporter is awesome however other exporters are complicated and I don't really trust them <img src="{SMILIES_PATH}/icon_e_biggrin.gif" alt=":D" title="Very Happy">