Spirits suck... your mana

So there is this one card I really like in Hearthstone called Mana Wraith. The reason I love it, is because it is such a unique way to win. It gives the game a twist, which might give you an edge on the battlefield. That is, if you own another cheap minion and your opponent doesn't. I would like to see more of this minion, but it sadly isn't that great.

So I came up with the idea to have a minion that gets stronger with each mana spend to cast it. Because who would want that, right? No one expect for me and my crazy ideas. But take a moment to think about it. This card would make so many other cards / abilitites more useful:

Elusive Banshee = 2/3 for 2 mana.
With Mana Wraith = 3/4 for 3 mana.
With Chieftain Scarvash = 4/5 for 4 mana.

With Naga Sea Witch = 5/6 for 5 mana.

With Venture Co. Mercenary = 5/6 for 5 mana

This card also makes Piloted Shredder a tiny bit weaker. Making it possible for the player to get the 0/1 Stealth minion blocking a slot on his side of the board. That is, unless the player can buff it of course. 

Anyway I like this idea. I hope you guys like it too. Let me know what you think of it!