Ashley I think its a good move for Scirra to specialize in creating a kickass 2d game dev engine and not mixing itself in the 3d world. Though a bit skeptic and risky in leveraging in HTML5, but what the hell if it makes things get going.
I'm a Unity Dev but if possible I prefer to do 2D games in C2. Doing things in Unity is easy once you get the hang of it but somehow I still find C2, ok for quick 2D gamedev. Exporting to mobile in C2 is different though, I hope C3 can address seemless export, or tie up with ludei or — Tom This might be a good selling point for C3. The only convenient way to export is via nw.js and web.