Increasing the surface area of an electro magnet
Even you are not specify the holding or attracting “strength” of your electromagnet, 
increasing the area of your pole tip, you spread the flux and increase the leakage. 
Usually conical, or sharp pole tips design resulting a flux density gain especially in short distances. You can see this in magnetic tweezers. 



The pole tip of your core also highly related with the dimensions of the object you are going to lift, because the ferromagnetic object acts as a mirror of your electromagnet core. If your core tip area is much larger than your object, then it will shift to the edge of the core. Good performance starts with an analogy of 0.8:1.
In your case you can construct a “jacketed” electromagnet in case of a holding electromagnet desired, or try to make the coil longer (longer core) increasing the magnetic lines return path and strengthen the attractive force. 

So I think the answer is no.

EDIT
The traction force of the electromagnet will be



where
P is pull in Kgr, Ag the cross sectional area of gap, lg the length of the air gap in cm, and NI is the ampere-tirns. (Charles R. Underhill "Solenoids Electromagnets and Electromagnetic Windings" 2nd edition NY 1914)