The question is a little more complex than whether or not I simply need block. Its more about threat. I have found myself with badges to buy the Unwavering Legguards. I also have the 2.4 badge legs. My real question boils down to which is better for threat out of those two items? The second part is, if Hit/Exp is better for a warrior should I worry about stacking tons of Block too?
get to at least the point where your specials wont miss and you wont be dodged, i believe 5.5 % hit and expertise, after that get as much block value as you can while still trying to increase your hit/exp. (after that point hit and exp has lower return although still good to have)
basically what im saying is if you have 900bv but only 2% hit thats very bad because your gona miss alot of your shield slams.
example in my threat set i have 9% hit, 10% expertise and 635 bv.
9% hit to not miss against a level 73 boss, 6.5% expertise to avoid dodges completely from a raid level boss.
That is 142 hit and 26 expertise skill respectively. After that, Expertise still acts as a better threat modifier for you than SBV all the way up to 55 Expertise Skill (13.75% parry reduction). As much as SBV is a great stat, it takes a backburner to both hit and expertise for a threat comparison. That doesn't mean going with 0 sbv is a good idea though, you want to keep at least SOME of it (300-700 is the range I see in end raid tanks, so there is obviously room for variation), but for your exact question, the 2.4 badge legs will outthreat the unwavering always unless you're above 55 expertise skill.
This is a mistake i was making on a regular basis until very recently. I had been taught during a time when expertise didnt exist that i should focus on SBV and hit (but never gem for it) and i will max out threat. When i put on my threat set before i knew better i was at around 900 SBV but my hit was at like 22 and my expertise was like 17. This obviously was a flaw on my own part in mismanaging my priorities. My threat set now uses all of my core tanking pieces (teron gloves, badge gear, shard of contempt, SSO neck) in combination with dps pieces to get the max expertise. Once there i swap out a few pvp pieces (bulwark of ancient kings over T6 chest and S2 helm over T6) and i am now suddenly at my hit cap.
I also noticed myself drop down below 490 defense rating but with the added resil from the pvp pieces i am still well within the uncritable range and now i dont have to worry about so much pesky avoidance getting in the way of my rage generation. This is a set made purely for threat generation so if you are still worried about taking large strings of hits, adjust accordingly.