User blog comment:ClariS/A Moment for Clarity/@comment-5764133-20130416124510/@comment-4881935-20130417151822

Go talk with more people. Most people will heavily disagree with you on Clairty being the 'best' support spell. Many of them will even say it's the worst spell or it's only there for newbies.

Secondly, with a 180 second cooldown, they can't 'spam at will'. The cooldown is way too high for that to be viable unless they are builiding mana or mana regen themseleves, which in turn would negate the overall usefulness of Clarity.