A few questions about Ulduar transition

[Flint81]

I've been a long time lurker of this site, which is an amazing one, and finally decided to register. In the short time I have been in the new content, I've noticed a few things, and since none of the other tanks in my guild are plate tanks, thought it best to inquire about them here:

1.) My shield block rating has always been strong, but I'm wondering if in Ulduar I should take strides to instead focus on stacking my dodge and parry.

and for my main question about gear in ulduar:
2.) What is the deal with the pieces in 10 man that have no defense? I recently received the sword off kologarn and I'm wondering if replacing a few stam gems with defense and using it for its high dodge hit and stam would be a smart move.

Thanks,

Flint