It would be nice to be able to load saved games from other designs. This would allow for a designer to create a trilogy, let's say, and the player could use the same party throughout all 3 designs.
There would need to be some way for a designer to specify which designs, else we would get people trying to load saved games from non-compatible designs. There would probably also need to be a way to check that the global info and the databases matched for each of the designs, else the player would not be allowed to load the saved game.