I've been trying some other strategy games lately. I quickly ended bored of those, unlike EU. That made me realise one thing: EU AI isn't perfect for sure, but still, it's a bit more clever than "throw mindlessly all my units at the ennemy and hope to win even though I'm outnumbered" or "systematic DOW when we share a border",... In many games, the whole single of a diplomatic AI is a joke; it's usually very dumb, the kind that refuse any offer (although it might come up next turn/month to offer you the very same offer, ie diplomacy restricts to accepting or refusing AI offers), or lunatic AI that will declare war on you, do nothing and after a while just offer to white peace for no apparent reason, then ally, break alliance, DOW, sit, peace,...
EU has it flaws, but to me, AI is where it shines.