I'm guessing they mean with some type of procedural generation or another randomization approach in mind that creates a bunch of new maps, bosses, vehicles even!
Advance Wars, if I recall correctly, has a hand-crafted set of maps and battles structured in a campaign story. So once you're done, you're done. Replay-ability is a bit limited.
I absolutely loved Advance Wars and my brother and I played the heck out of it growing up!