I once and will still use a program called GameMaker and it has something that be useful for the Blender engine, while it makes 2D games it does have a persistant setting for objects and levels.
What would be nice to have in the game engine would be persistant flag for objects, levels and be able to set it through python. This way, say you have a spaceship and it’s too large for it to all be one level, so you break it up into smaller scenes. You can set the scenes and the character to be persistant and then the character from that scene will be able to go into the next scene without linking or copying the character in that scene. Even better, with persistant on in the two scenes you go back to the first one and it’ll be just the way you left it, if you toppled some boxes they’ll be toppled when you get back.
Also for added flexibility be able to set it in python, then you can turn persistance on and off for any object and any level at any time.
What do you think, good idea?