Would Manaflow Band Be More Balanced As Lissandra's Passive?

A free spell cast, but doesn't restore any mana or energy. I feel like the restoration part is the main problem of the Rune, as it provides way too much free mana in the early game.

I feel like the cooldown would need to be slightly decreased, but I would also prefer this version rather than needing the mana to cast something. I've had multiple times now where I could secure a kill in the early game if I had the mana to use one more skill. Manaflow Band was up, but unless you already have the mana to cast a skill in the first place, it's useless.

(And while we're at it, can we please give Lissandra a new passive?)