I think the changes bubbly suggested is pretty good. Personally I would keep Chansey over Gastrodon and use Bulky SD Scizor over Jirachi. It covers Reuniclus, Latios/Latias, Celebi, and can revenge kill Terrakion/Virizion. It can even beat SubCM Jirachi.
Breloom can be an issue so I would use...