http://www.gamesas.com/index.php?app=forums&module=post§ion=post&do=reply_post&f=118&t=1173417
Well according to GI article Skyrim: Building Better Combat
If you come face to face with another wizard, you’ll want to keep an attacking spell in one hand and improve your defense by equipping a ward spell in the other. Suddenly, magic duels become much more interesting, as you must attack at the opportune time, use the ward as a shield when your opponent is casting spells your way, and manage your magicka level by consuming potions.
There will be some sort of Magic Ward spell
So actually
Force Field type effect, blocks all incoming projectiles.
Force Field, can block projectiles and foes can't move through it.
Force Field, but a small one - circular with a few feet radius.
Buff that reduces damage, but is more effective than in Ob.
All of this types can work in game if dynamic magic system works
for example dynamic ward protection when player need cast spell at time of enemy cast to nullify incoming danger thats like timed block with shield or parry with weapon but for spells, thats Magic Ward will be modular and composite from different spell effects for example
overtime protection can be achieved by Skillful mages thats have great reserves of Magicka to maintain such spells while apprentices will use more adrenaline action counterspells shield wards
Spellshields
http://tesnexus.com/downloads/file.php?id=21629
http://tesalliance.org/forums/index.php?/files/file/780-duke-patricks-combat-magic-ii-duke-patricks-incursion-into-fortress-of-fear/
http://www.youtube.com/watch?v=ZTOynB6Z-Rw