The valorous were second only to maly legs if i remember correctly (pre-Ulduar), so I do think it's an upgrade. Be warned, you're a bit low on hit rating and switching out your legs will take you even lower, it might be a good idea to make up for it somewhere else. Maybe use an exp-stam gem on your new legs, and switch out that agility for another exp-stam gem.
What do you mean you're gaining +block? there's no block on the valor legs, or do you mean block value from the extra strength?