Hm no we dont?I think it's just further evidence that the word is meaningless when it comes to game systems. WotC has effectively destroyed the word. It has a definition for books, but not for game systems. We need new terminology.
In boardgameing its relatively clear. We just need to stop treating RPGs as books, and instead as games. The book is just a medium (among others like digital implementations) to give the people the rules to the game.
A new edition of a boardgame is not compatible with the previous edition or any of its "addons" etc. thats why its a new edition and not just a new print.
Of course how much changed mechanically can still varry, because there its hard to define, but having the compatibility as the main distinguishing factor is easy and useful (you know if you can combine it or need to make/buy new things).






