I think acquiring hitters with high OBP is the #1 objective. Having power and being left-handed are certainly desirable qualities, but this team's OBP is so poor across the board that getting anbody who can get their ass on base is the most important thing right now.
Dunn isn't the answer to fill that need, but he's here and nobody is going to take him, so time is better spent figuring out other ways to improve the team that don't involve moving Dunn.