I used Smokescreen because it fits thematically with the Blind Status ailment. I really didn't want to have the Air Rain provide any sort of CC for 5 turns, since that would be unfun (or broken, depending on if the character gets the immune to stun talent). I also didn't want Invisibility Rain because that would most likely lead to easy combats. As it is, melee can do their attacks and rangers/mages can still do their AoE/Projectile attacks through the Smoke via indirect targetting.
I don't plan on adding monsters to the encounters, since that would turn my mod into a heavyweight mod (incompatible with other mods that change the map). As it is, my mod is lightweight and can be dropped/merged into nearly any other mod and have its effects. I am willing to give enemies a global buff though, like maybe +1/2 to their Speed/Constitution so that they hit more and last longer in combat.
Thanks for the feedback.