They are both the exact same.
Falrics has block value, while Rimefangs has parry. Nothing more and nothing less.
Dodge is still useful in ICC, 1% dodge out of ICC is still 1% dodge in ICC. The debuff is applied after diminishing returns so if you had 25% dodge out of ICC you will have 5% inside but that does not diminish the value of dodge since it is still better than parry. So if you get an upgrade that gives 1% dodge than your total would be 6%.