Agreed.
Sometimes it's best to leave anomalous cases to be dealt with uniquely via event if conditions merit rather than try to find some grand unifying rule to tie a bunch of them together on a rather weak thread.
The problem is that Paradox events have the tendency to be incredibly deterministic (in the sense that Japan will get an event for demanding Indochina no matter what) while actual game mechanics would make the engine more flexible and more capable of adapting to different situations.