I had about the same thoughts when this card was introduced, as a concept back then.
Now I think that it is on par with other such cards like Seiryu or Suzaku. Maybe it's slightly more powerful now that it can be summoned by Geomancer, apart from the other Unlinving summoners.
If you are lucky to draw Wonder + Genbu consecutively then you probably deserve to win, as is the case with Wonder + Suzaku for example (8 + 8 + 3 X 10 = 190 dmg).