Oh, hmmm. Heh. What would happen if Spain wasn't in the picture? Let's see. We wouldn't have massive amounts of Catholics around the world. Also, the Aztecs and the Inca would still be alive, but the Portuguese would just take Spain's place (oh wait, Portugal declared independence of Spain in late 1300's so no Portugal). Arguably, they would've still died off by some other colonizer.
Spain didn't contribute much? They sure did. There would be no Spanish Civil War to test out Axis Power's weapons. This would also link to no Carlos V of the Hapsburgs, who led the HRE, whose family eventually became Austria after the Thrity Years War. Where could all this point to? It points to Spain being a strong presence in history. Also. If you're talking about world powers, only Russia and Turkey would be on this list.