It's interesting the number of threads that turn into exporters because of performance X reason. Personally I think the big weakness is that C2 isn't friendly for complicated game development. Object structures, team asset management, lack of modularity, lack of Object>Sheets so on etc are so problematic. Personally and this is just an opinion if these problems were fixed
Object Structure = Scene Hierarchy with Object Pattern(ie part of scene graph of objects are saved as it's own object, similar to container, but more flexible)
Team Asset Management = art, audio files should automatically sync when updated with the requirement of manual updating to associated links.
Modularity = better re-use of code chunks.
OOP = More logistical design for creating a game that offers better more friendly development patterns to non experienced programmers. There is a reason why OOP is more common than Imperative programming. It's easier to understand, read, write and control in development software.
Better Plugin control = Moduals and plugins should be per project and stored in the project folder. So that when working in a team the plugins and modules are already ready to go.
Sprite Object replaced with SpriteBehavior that uses controlled texture atlas. This would increase performance, reduce memory, and solve poorly made projects. This also means that SpriteAnimator should also be a beahviour so that SpriteRendering and Sprite Animations are not linked.
If these problems and I did say problems were dealt with. I don't think there would be such a cry for native exporters. I feel confident that the average performance of games would significantly increase. But this is all speculation.
Lack of performance is a symptom, not the cause.