[Kameron8]

The sheer amount of focus needed to cast the spell makes the suggestion sound reasonable- until you realize that both users can use expanding ice and thus mitigate focus cost by making their ice fields spread out over most of the battlefield easily.

I suppose if you want to group three or four will based Verglas characters together, you could do this, yes. But I can't imagine having three people spam expanding ice would be all that threatening in some large team battle -- in fact, just throwing together three Evokers or Wretched Oil spamming Hexers would likely get the job done much faster and for less FP. All this would really do is clear up the inherent confusion that crops up when staring at a battlefield filled with ice tiles. Which ones are mine? Which will disappear next turn? If the enemy is on an ally's ice tile, will they be immune to my expanding ice?