If we were able to get another quality striker alongside him, who offered a different style (more agile and pacey etc.), it'd be a nice a combination.
I would be quite content to start the new season with Tosun, player-X, Niasse and DCL as I feel our real deficiencies are in other positions.
For me DCL shouldn't be anywhere near the team tbh . Niasse also although as a sub I could live with him. Ideally we would have player x and then another player to come in . A lot depends on who's manager and if we are going to play lone striker (which I don't like and don't believe touson is suited too)