Riot should add back Clairvoyance and rework it

It should be a 150 second cooldown. Place a ward up to 1200 units away that gives vision (900 range) and reveals stealth and true stealth (limited to one at a time).

I actually think clairvoyance actually could have been a cool or useful (albeit matchup dependent) summoner spell that could have been used more often by supports or mid laners. I don't know if this is exactly what the numbers should be on it, but I think it'd be an interesting idea to bring it back into the game. If not clairvoyance some new summoner spell.