A striker by definition, particularity a prima punta, is required to score goals. If his goal scoring ratio is abysmal, then by definition he is shit, as he is failing to do his job efficiently and effectively. Borriello falls to ground easily, so even if he can hold up the ball well, he also manages to lose it quite often by being a constant diver.
@Kasaki I'm sure Matt wasn't suggesting that we should have a Higuain caliber player as 3'rd choice (not even Barca and Madrid can afford that), but a strike force of Cavani, Quags, Matri, Destro, Vucinic, and ADP is significantly superior to a striking department containing the likes of Cavani Quags Vucinic Borriello and 1 or 2 random names.