Reminder of topic:
I'm trying to get us all to distinguish between irritating "pet peeves" and things that we want badly enough that we'd pay for them.
Regarding the SaveGame file editor:
Because SEIV is so complex, the possibilities are awesome. For instance, you could make up your own disasters and roll dice for them, then implement them with a SaveGame editor. You could have quests; you could have sci-fi literary scenarios. You could play it like D&D with a "galaxy master." You could override the results of SEIV combat and insert results based on your favorite combat game. You could use the editor as a "deus ex machina" to turn an end-of-game mop-up into an epic struggle (the aliens from the galaxy next door are scared of you and so they just gave your pathetically weak opponents a large advanced-tech fleet and maybe some ringworlds), and you could use it to set up the game anyway you want -- tech levels, resources, starting planets, etc.
Regarding PBEM if a SaveGame editor existed:
There are ways to verify if a file has been tampered with. These could be used to prevent PBEM fraud. (Plus, mail fraud is a felony, but PBEM fraud is a mortal sin.
) However, there are "legal" ways to "cheat" by using strategies that take advantage of loopholes in the game. Most players in PBEM outlaw these with "house rules" and simply trust their opponents to obey them.