[Sombre]

Yeah playing with VP is the answer. If you set the AI to a difficult setting and aggressive, play on a small/medium map and make each province worth one VP, game ends when someone has 50% of the provinces or so,... well then you have an actual goal to chase. The AI doesn't seem to take VP into account (as far as I can tell) but it certainly likes taking over provinces, so it does much the same thing as you. I'd also suggest roleplaying a bit,.. for example you might decide you're going to get full use out of every unit type available to you (even if they're a bit crappy) or try to use low level summons a bit more. It's not playing badly on purpose, it's just a matter of being varied rather than uber-efficient.