Why hasnt anybody said it yet?
Let me take your imagination to a new level. Picture this: Dual wield shields. Aegis+Ochain.
Cant use a weapon but who needs it.
On a more serious note maybe something like
'Occasionaly takes damage for a party member/ally'
'Occasionaly pushes all or some aoe damage to the paladin'
Some kind of counter effect to a block.
'Each block has a chance to reduce the cooldown of reprisal'
An afflatus solace or impetus type effect.
Each block grants a stoneskin effect or each consecutive block increases damage mitigated.
'Taking magic damage restores x% of damage taken to mp'
Or even putting a spell on the shield like the twilight cloak has impact. Maybe a shield with aquaviel or blink or regen?
Yeah just throwing things out there. But imagine this once again.
Dual wield shields, with all of the above effects.