Haha, well the whole years vs turns thing is one of those game elements that you just have to think about as an abstraction. It's the same if not worse in vCiv4, when it takes you like 300 years to train your first warrior.
But back on topic... I think the spreading/receding ice is a nice alternative to having seasonal terrain art that rotates every few turns. It certainly would be less graphically and computationally intensive. Though one way to simplify the seasons would be to have only two, a winter/summer dichotomy like in the Total War series. But I think at the end of the day, while it would be cool, it should only be added if it actually added to the gameplay.