I don't think he's that bad, goal scoring wise he's pretty poor. But he's very good at bringing others into play and being strong in the air / holding it up. Like i say i'd only have him as a squad player.
Again, we shouldn't be bringing in "squad players" we have enough of them. We should be bringing in first team players to help improve our position. I see Osman, Anichebe etc as squad players and they're a hell of a lot better than Di Santo.