Ok so the other day a couple of guildies and I were bored in haven so we started discussing silly ideas of ways to spruce up the game. I think we stumbled onto something pretty neat, so;
I propose a new floor. Ice! The core mechanic behind the ice would be the ability to slide. Tap W (or your respective movement key) once and perhaps you slide forwards 3 blocks?
PVE : It would make for another stratum possibility, fighting monsters whilst sliding around all over the place, and the monsters doing the same.
PVP: An ice themed lockdown map (other than Frostbite or Avenue) where the floor is ice and you slide all over the place whilst fighting players. Maybe you slide further depending on which class you are, maybe weapon charges can send you flying all over the place. Or to be more specific, maybe a Triglav (or any charge that sends the player flying) is now extreme and sends you 7 blocks!? Or the brandish charge, instead of 5 explosions infront of you, maybe the player gets fired 5 blocks forward and there are 5 explosions left in his trail.
Haven: Maybe at winter we can walk up the slopes at the fountain. Turning the fountain into an ice ring for us to play around on.
Also, maybe fire based weapons such as the Fang of Vog, Ash of Agni, and Combuster can melt a section of ice, maybe trapping ice-based monsters or clearing the ice away temporally and making it easier to fight there.

Anyway. It was just a thought.