I thought AoM was made to test the 3d engine after AoE2? Maybe some gameplay concepts or code were saved, but I imagine the assets would have to be completely different
Yeah, Paradox Interactive makes a lot of games, mainly Grand Strategy Games that attempt to simulate (alt) history. Crusader Kings is medieval, Hearts of Iron is WW2, etc. It's a bit like Civilization on steroids with a daunting learning curve.
CC is actually really good if you know what you're doing. The only issue imo would be PR spamming