I don't think seasons have enough of impact at the moment.
Seasons impacting just food and travel feel somewhat silly. If it is to be more important, it should affect more things. Like recruits - less people showing up during spring and fall to work on their fields and more during winter or something.
Also, it would be nice if it allowed soldiers to cross rivers and lakes during winter. That would probably change how the game is played quite a bit.
To be honest, the current design is somewhat disappointing and unless it is planning to be improved, it should probably be removed.
