Theres only 4 mages ingame, sorc sps sh and necro. So why you come here with your wc talk suprises me. Op didnt ask aything about buffclasses, he asked about mages with shields.
To op like i said, shield is good for extra defence. And like Modoy explained further its for pvp.
Shield/sword pvp
Staff for pve
Rechargers/buffers = different story.
@jzoo oh you use 1 handed blunt for faster stun? Please tell us more how awesome your knowledge is.