I really liked the concept at first, but the nerf really seems to have ruined it.
As people already stated, this card was strongest (read fastest) when used with relatively smaller creatures (so no Titans, Armagio's or Voodoo's). After the nerf, the upgraded version just kills them to fast, giving less turns to do damage and a worse attack/-hp ratio then the unupped version.
When this card was "released" I was happy, but after this nerf I'm like meh..... At least keep the attack/-hp ratio 2/1.