His influence was negative on the young players around him. Eriksen, Holtby, Townsend and Lamela had major confidence crisis with him up front to aim for. Are you SURE you want to risk their development with Soldado? Are you sure you want to risk the potential Alli has? It could really mess up other players like Bentaleb, Dembele and Mason if they keep putting through balls for someone who is either not there, is muscled off or chokes?
IMO he is a liability and it's best for HIM to leave. He's miserable in this league.