You have no special sweepers, and no Ice move. You need at least one Ice type attack for Dragonite.
Also swap Sawsbuck for Venusaur, you need a special sweeper, and Volcarona will cause for too big a rock weakness on your team (no resists and 4 weaknesses, as trio gets OHKO'd by anything thanks to 0 IV's and a -sdef nature, which you need to activate sash)
perhaps Tornadus can be your rain counter? As Grass knot OHKO's Hippowdon