Well, I got away with it. There were no attacks on my castle today, and despite leading by only 3 points, the third-place player in today's league rankings apparently did not log on and take back the title. So, I was able to achieve a rank of second place in the Minion league and advance up to Grunt league, despite being terrible at the game.
I kind of wish I'd gotten some form of comeuppance there, but I guess it's not too late. With my castle now abandoned, it's likely that over time, it will be beaten by ambitious newcomers and fellow slumming high-level players and my total crowns will dwindle to nothing. That's the way it should be. I've uninstalled the game, so I'll never know, but I can't believe that something so out of balance can remain that way for long.