Hmm, well, I'll be answering.
I say Sawsbuck. While Leafeon has much more Defense, Sawsbuck has arguably better dual STABs. It has a powerful STAB Return, recovery + STAB in Horn Leech, and a deadly move in Swords Dance. It can be a deadly sweeper in Sun, or with Sap Sipper, a nice counter to Amoonguss's Spore. It can Baton Pass the Sap Sipper boost to a Sweeper, who will gladly sweep the opponent's team, such as Emboar, or Cinccino.