Seeing as how the plan had the support of most of the nobility save a few of Alanna's fiercest loyalists, I'd say beneficial. And it's not like it was our first round of scorched earth. Before LN, PeL had already been split down the middle and a whole duchy leveled to get rid of a few entrenched people.
Really, you should focus on preventing the problem of unbannable Royals instead of panicking about what to do once you've run out of options. You don't have to be a mindreader to know if someone might end up being a problem once they have a crown on their head. And if they do become a troublesome ruler and you want them gone, then by Jove, start a rebellion and execute them/kick their ass to another continent instead of giving them a license to make your life miserable later on.
Think ahead!
You completely disregarded my question. Its not whether or not it was a good decision in that one instance. Its whether or not having to destroy a realm as the only possible recourse is a reasonable thing to include in the game. For all future cases and in general. That is what I believe is toxic.
