Afaik the new stam enchant is not available or it is hiding very well from the world. Defense to shield is very valuable atm. One of the best slots to have it since the stam alternatives are quite lacking especially post patch once 40 stam to bracer goes in.
Unless the +block value stacks it just doesn't seem worth it to me. Maybe if they had a large enough strength enchant or that new stam enchant but certainly not the block value.