Changes to the rules starting with the letter G (Graal and Galtran).

I remember one streamer stepped away from his computer during his turn, and while he was gone, his hero was attacked and killed by an enemy hero before he could take his turn. When he returned, this streamer uploaded a recording of his stream to see what army the enemy hero had. Is that also a sin? :)

Conditionally, yes. You can ask your opponent what happened to your hero and what killed him, and it's up to the opponent to decide whether to answer and how accurately (replaying the turn will show who killed his hero) - that's how people used to play... now there are different games, different paces, and maybe it's worth adapting and allowing something.

If the game cannot be hacked, set a limit on digging (125-131), even if you remove the bonuses from the cartographer and all magic, there's too much free stuff in the first week.