I say trade Big Ben for a top 10 pick. Pick a possession WR in the draft to eventually replace Ward when he retires or is forced out. Give Dixon all of the support he needs to be successful (including placing more emphasis on the run) and move on.
While Big Ben won games and was able to make a lot of big plays, I still say he's not as good as a lot of the analysts say he is. He holds the ball wayyyyy too long and is indecisive when blitzed (translation: he doesn't read the blitz well at the line and has to rely on the line to give him enough blocking to help him find the hot receiver). His sack total is among the highest in the NFL on a consistent basis. It's not always the fault of the line. You'll see him double, triple, even quadruple pump the ball before he decides upon a receiver. Sometimes, he was able to make up for his indecisiveness with his strength. He can brush off blitzers that other qb's would fall prey to. Nonetheless, Dixon counters with speed, and can add a double threat to the qb position in Pittsburgh.