I feel one reason that riot had to remove mana potions, is to make clarity more widely used. Take 
, a heavy mana user with his bombs. Taking a support item + flask could work, and instead of normal set on summoner's, you could take clarity. With a flask/new flask and clarity, you should not have much problems.
No one will take clarity anyway. It sucks late game and you have to give up a teleport of a def spell for it. Totally not worth. Better mooch off of poor jungler his blue buff.
They need to reduce the CD of clarity though , as it is currently way too high to provide a consistent enough amount of mana regen.
Seen Clarity cooldown, i'd still prefer taking TP, back and buy mana items and come back to the lane
The only problem is any other spell is a better option. Even double heal.
