Arsenal needs one more striker, in case of injuries. He needs to be a blend of Walcott and Giroud or to bring something new to the party such as dribbling skill. Fast and tall. Fast and skillful. Or tall and skillful. So that even if one or other of the existing strikers is injured, we can get some contrast into our attacking options.
Fast, tall and skillful would be even better but such a person costs too much because he is Cristiano Ronaldo. Two out of three will have to do.