I often let the AI handle skirmishes where my military or general vastly outmatches the opposition. The battles are half the game though; I have a friend who played the game like you describe - he got bored, said the game was easy and stopped playing - never admitting that by letting the AI run his battles he wasn't really playing the game at all, or getting even a portion of the enjoyment the game offers. I absolutely love the campaign-level play, but I try to play any battles that aren't a foregone conclusion - play on hard and you'll be surprised at how often the AI will do something that surprises and challenges you...