I dunno about MP, I never really got into it, but AI was extremely easy even on the hardest setting.
Campaign was terrible.
The whole explorer thing didn't do it for me.
Home city was coolish, but I didn't like the whole "The more you play, the better stuff you get, because being more experienced isn't a big enough advantage!" thing.
Units weren't as cool.
Unit upgrades were sorta... generic.
None of that's a real reason I didn't like it, just things I don't like about it, I more just didn't enjoy playing it compared to the other 2.
Beware the Australian Fridge
Veraam:
One with power = Corruption
Two with power = War