Whatever method used to fix this issue is fine with me, as long as it stops happening. As has been noted many times throughout the forums, this issue is a "gamebreaker." Either the AI needs to behave appropriately based on the risks involved, or if that can't be done, then the risk of total empire destruction needs to be removed by changing the rules/mechanics of Sovereign death. Plenty of ideas have been thrown out there already in other threads as to what those changes could be. I don't care which method is used, it just needs to change.
What really gets me is that a couple weeks before the game was released Brad himself gave a word of warning to players that sending a Sovereign into enemy territory was extremely risky and should rarely ever be done! Yet for some reason, the same "advice" wasn't given to the AI...
It's the equivalent of a chess AI sending it's King beyond the front line without protection. It's ridiculously inept behavior that totally removes the strategic challenge of the game. It's become the main reason why I have no interest in playing the game as it is. Hopefully it is resolved sooner than later.