I did the very same thing, dear hoho
I had not finished the vanilla campaign at that time, as I was completely stuck in the eighth scenario. Time then passed and I finally found myself playing with the campaign of the expansion, which was absolutely a wind of fresh air. I really like its wide-ranging touch that leads you to head to Egypt, Greece or Scandinavia. The idea of a benevolent titan on your side, Gaia, is quite revolutionary in itself. It's not everyday that a millennia-old and pre-gods deity decides to partake in the war in your favour