The Bengals have won the AFC North and are one of the best teams in the conference. One of the reasons that the Bengals have been so successful this year is due to the players that they have. If the Ravens had some of these players, they might have a better record this season. Here's some players that would fill some holes on the roster:
Dunlap has been a dominant pass rusher for the Cincinnati Bengals with 13.5 sacks this season, a Bengals franchise record. The Ravens have had issues with the pass rush ever since Terrell Suggs went down and Dunlap would definitely make a difference.
Atkins is one of the best defensive tackles in the NFL and this year is no different. Atkins has been his usual disruptive self this season with 10 sacks and another Pro Bowl nomination.
The Bengals safety has eight interceptions and 13 pass deflections. In short, he's the playmaking safety that the Ravens have needed for the past couple of years.
You know the deal with Green. He's got the perfect combination of height and speed and he has the ability to make almost any catch. Green is one of the best receivers in the NFL and we know that first hand.
Personally I would go with Geno Atkins or A.J. Green. Atkins is an elite defensive tackle that would give the Ravens a better pass rush and Green would be the elite receiving option that Joe Flacco doesn't have right now. Who would you choose?