As you say yourself, we will use various formations, which means we will sometimes deploy two strikers (i think it will be quite often, and in the case with only one, i think Tevez will be one of the two behind for example). Morata is clearly not seen as a true centerforward, so we only have Llorente who could really fill that role to perfection. Morata might get some times pairing Tevez anyway, but we will play in a different way when that is the case. I can see the point in getting a centerforward, but i don't really think Hernandez is what we need..