What if Clairvoyance....
{{summoner:2}} Gave you vision of everything the enemies could see for 3 seconds, rather than just revealing an area? Would make for a fantastic vision control summoner, giving you vision of all enemy wards and invisible enemies, but sacrificing a summoner spell slot in return.
will sometimes burn his ult just for vision of the enemy champions. The current clairvoyance, at least, is on a cooldown of just 60 seconds. Maybe if it were more like flash's cooldown? I don't know this still sounds really strong.