MArcomage

I like this concept. It wouldn't be too overpowered unless it's put in a low-cost quick/swift focused deck, and those decks aren't really threats.

Much like my Momentum concept, but I like this better.

You appear to confuse over- and underpowered in meaning.

I think it's too cheap at three gems. Using it with just one Quick card more than pays for itself.

Modified a little to reflect cost.

I like it.