I said that wrong, I apologize. It was that moment when you think one thing but you say another thing (except I typed it out).
I meant attack is more important for artillery and mid range fighters.
Sorry for any confusion I caused.
But thinking about it further, for artillery only, it depends what type of purpose you are using it for, such as taking down a wall or troops. If you are trying to take out hoplites, rams are the best to use, as it hitpoints are high which is good when getting bombed upon, and its attack is high enough to kill an entire hoplite. Mortars are the best to take down walls and kill SGs, but they cause huge damage to your own side if you get bombed upon.
The attack is always most important for mid range fighters.
Once again, I'd like to apologize for my previous error.