Well blizzard has vastly improved how effective block is for warriors. The amount of mitigation we gain from blocking a hit is no longer trivial in nature. If you spec into all the block talents for prot warriors and get pieces like this from naxx then you will have a VERY high percentage to block which immediately translates into less damage taken. Shield Block Value is a key damage stat and something that we get alot of from strength (the wall of terror giving us a total of ~31 SBV from it alone). In essence the wall of terror has really given warriors every stat that they could desire in one little piece. If you do want to up the block value on it (cause who doesnt!), then you can go ahead and add a titanium plate to it from blacksmithing for an additional 40 SBV.
"If I'm doing a fight and I need more threat... I try harder. If I'm doing a fight and I need my taunts not to miss, then I wear hit." -Veneretio