Only solution which I can see:
Better guide, tutorial, manual for scripting or plugin making. Plugin and simple change automation for runtime and editor, which simplfies work enough, so users can do their own version of stuff. Case, which in overall should make scirra work easier too.
Sometime like:
*Plugin maker - with set of rules to avoid compatitibility problems. User should be able to modifie simple templates and add features to templates of official plugins. Allows users to do small changes to plugins to add some expression, condition or simple change.
Yes, I've found writing a plugin for C3 to be more difficult than writing portable components for Unity (using C#) or Unreal (using Blueprint - I don't mess with C++, haha), partly thanks to the somewhat bare-bones SDK documentation and lack of tutorials for writing C3 plugins. Of course, a simple, baseline C3 plugin is just more complicated than a simple, baseline component for other engines, so it's a bit of an apples/oranges comparison. But the bottom line is there's a lot of friction with getting started writing C3 plugins. Having some built-in software to help manage complexity in C3 and some plugin programming tutorials would be pretty great.
In general, C3 logic isn't too easy to encapsulate and port between projects. It's actually somewhat dangerous to do - if you do your event sheet/object copying and pasting between projects wrong you can wind up with a corrupted project file that can no longer be opened. (I recommend Plastic SCM Cloud for an easy to use, binary-friendly version control system, for what it's worth!)
Anyway, I digress... there are already suggestions on the ideas platform for ways to address all these issues, but sadly they're mostly buried.