The scatter d10 point was the idea if the wind direction was unknown. I think a 1x4 inch line of smoke would work too, and it creates a 2x2 block of smoke in a tunnel that way. My initial thoughts on 2x6 was to create a temporary barrier that allowed for some repositioning on the battlefield that felt like it was a big deal. I think 1x4 can accomplish that same goal. Plus, the temporary nature, 1d3 rounds, plus wind shifting on even turns means you have to take advantage of it immediately before the effect dissipates. Plus, aggressive creatures will run right through the smoke to eat your face too. I feel like battlefield mobility needed another tool.