Hmm... well, I for one can't see any real problems why it should be hard to implement a saving function in hot-seat mode. Since it's basically just as in single player... only you have two players ? O_o
hehe, yesterday I played antarctica or whatever the "Small" Ice Island is. And we played for 2:30 hours... We actually say until 4 AM
since there wasn't a saving option. (Then again, he's still learning the game)
Oh and the 3-4 hours is on a large map with the computer... I wouldn't be surprised if it takes longer against a human player