Remove the 'shield use' legacy from our belts and add 'Threat generation' as the base stat. That way our threat generation can be better balanced with increasing DPS as people progress from 3rd to 2nd to 1st age weapons
Keep shield damage/bash and smash legacies as they are but bump up shield damage across the board to make up for the loss of damage from removing the 'shield use' legacy.
Replace the 'skill threat up' legacy with something equally useful such as +incomming healing, shield attack crit chance, imminent clensing countdown reduction etc etc etc.
Oh and combine the guardians ward block and parry legacies in to one. You can introduce one of the suggested legacies above as a replacement or just add a + tactical mitigation bonus to ward legacy. Your call.