I don't think you're beating a dead horse -- and I do think that a "more threatening" model where the you can have a continent sinks into the sea is something worth exploring. However, that would be a mechanic that was only available on higher strategic difficulties (which we would bring back for something like this), and which has its own sets of both benefits and pitfalls in some fashion.
In short, it's kind of a whole game mode in and of itself. Possibly it doesn't need to be a game mode, even -- maybe it's some sort of doomsday device that, once you interact with it (and it warns you), it causes the destruction of the continent in X more CP, but you get Y benefit if you can beat the overlord before that time. But this doomsday device option is only available when the continent is still tier 1-2 or something.
I don't know exactly the mechanics that we'd want to use, because we're pressed for time and haven't put a lot of thought into it yet. But I do know that, if it's something that can be done in a straightforward fashion along those lines, adding value for people like you who want that sort of thing without impacting players who clearly have no interest in being actively threatened in this genre of game... it's something that I'm interested in trying to squeeze in prior to 1.0. And if it's "bigger than a breadbox" of a feature, so to speak, then that's something to explore sometime post-1.0, but still something I want to look at at some point.