Need a way to easily migrate without having to do a full rewrite. Release the CocosCreator C++ Lite engine as Cocos2dx C++ v4 with some documentation for migrating from Cocos2dx 3.x to Cocos2dx 4.
Forcing people to rewrite using Creator editor gives them an option to consider rewriting using any other framework. If they have a clear migration path they will have no reason to look elsewhere. Then Cocos team also won’t need to maintain two C++ engines. And all the existing code and projects will still ‘fit’ in the new vision without anyone having to worry about the the engine dying a slow death.
Once our existing code is using the new engine, we can try developing new parts using creator and build it together with existing code, slowly migrating parts of existing projects to creator or continuing using the CocosCreatorLite/Cocos2dx 4 engine directly without the editor, etc…
EDIT: I want to add that this has already been suggested by cocos team as an option, but they should do it quickly to remove any fears about the core engine getting ignored or slowly dying out.