^ In other words, the AI isn't smarter on higher levels.... it's all about numbers.
Agreed... that catherine has crushed my heart so many times...
No, they will most definitely bring more units because they have a production bonus. On higher levels the real warmongers will bring stacks featuring pretty outlandish numbers of troops.
Because they also get a bonus to research, they tech more quickly and can therefore bring better units.
However, that doesn't mean they will play smart. So their stacks may still be composed of a really weird mix of units. They will still suicide a big stack against unbeatable defenders. And so on.
And two elephants or two knights with more than a dozen catapults.
I suppose it doesn't matter. If they built human-esk stacks they would destroy humans king or better. If they built any 'standardly formulated' stacks we would code-dive and then counter... I suppose they could just randomly pick priorities or w.e. every time you loaded a new seed... but then we saw how CiV went with randomness.