Washizu's just a normal player. Even Fake Akagi being as sucky a gambler as he is is still a "professional" compared with normal players. The key was Washizu Mahjong made Washizu invincible because it maximized his insane luck and limited a mahjong player's skill. Players have to score insanely huge hands just to survive the rank bonus penalty. Akagi's particular game sounds insane, but really Akagi was facing Washizu at his weakest while Akagi himself was at his strongest, so that's what allowed him to make it so far.
Imagine if Ichikawa, who was second only to Akagi,was facing Washizu. Ichikawa can't see Washizu's tiles, while Washizu could see his. He also doesn't have a wall in front of him to feel, and likewise wouldn't know the tiles of his ally in the game. He'd be at an incredible disadvantage facing Washizu, even if Washizu told him the tiles in his hand.