I'm not seeing this played in place of Claydol...Stage 2 is infinitely more harder to play than a Stage 1 (barring Rare Candy) and he damages himself, leaving him open to spread damage + TM TS2 if they Candy into him. Not to mention Dusknoir's Power is just Bill with a damaging side effect and limitation; Claydol will usually net you a greater amount of cards. However, in a Dusknoir-centered deck (especially with that evil Lv X), at least you don't need to run Claydol then.
Now, next season though, when Claydol could be making a departure since they rotate about 4 sets per season (lol, uber-far-off format guessing), if there is no better substitute, he could see play for that purpose.