If the goal is to get good at the game then it is better to play 1v1. Practice from campaign or playing against computer is not as efficient as playing against a real opponent. If you play against the AI you also develop bad habits since you get away with things that does not work against a real opponent.
Yes, lets play 1v1 when you are a noob, get crushed, and ragequit. Playing against the AI has always been the way to get better. You only ever develop bad habits if you start doing bad habits in the first place. You obviously haven’t played against age2 DE extreme AI if you think that playing against AI can’t help you get better.
they said there will be modding support for the game, but unsure about the limit, let’s hope it will include the ability of adding new civs and even overhauling the game, these kind of mods always gives replayability to the game.