So I know the BS craftable belt and boots are considered BiS for tanks (warrior) since they have so much stamina and sockets for more stamina. However, the belt and boots I currently have - Shieldwarder Girdle and Charonite Greaves - both have nice amounts of hit rating on them (unlike the bad parry rating on the craftables). I've been thinking of picking up the craftables since I figure it's time, but I'll lose aroud 100 hit rating and fall even further behind the hit cap. I looked at gear guides at other BiS items, and only the cloak, wrists, gloves, and possibly gun have hit rating on them. How do you tanks go about being at or near the hit cap with all your Ulduar 25 gear?
If I am not totally mistaken, I believe that the neck piece from conq. badges has a lot of hit rating on it. Maybe "Best in Slot" Guides need rewriting, as 170 hit rating is, in my opinion, unacceptable at that gear level. DPS BiS guides (at least for warlocks pre LK as I played that class predominantly) had exactly enough hit for cap with raid buffs/debuffs, I fail to see how a gear setup could be best in slot if you are missing with some of your moves.
I would ignore hit/expertise unless you have threat problems. You can have two sets of gear and just gem/enchant one for threat and use your other set for progression. Hodir is the only place where I would make sure you max or are close to the cap on both. General is another encounter where you want to keep at least an average amount of hit and expertise. You should just tweak your gear depending on what sort of numbers your raid puts out. Most other fights though you can easily ignore threat stats and focus on EH.
Yeah, you don't have to be at 8% Hit and 6.5%+ Expertise for most Ulduar encounters. In my main set I'm at 5.28% Hit and 7% Dodge/Parry reduction, and I hold aggro just fine. I focus mostly on EH and avoidance.
But some fights like Auriaya, you want to be Hit-capped so you don't miss an interrupt. Other fights you just want more threat period. So carry some alternate pieces to swap on as needed to replace some of those pieces with no Hit or Expertise. The badge belt (56 Hit) is a good one to replace the crafted belt for those types of encounters. Or boots from Ignis (49 Hit) if you have those. Legs (66 Expertise) and trinket (69 Expertise) from Malygos are good Expertise pieces to carry around. Etc.
I wouldn't replace the belt for many encounters (none that i can think of at least). The boots, however, are just an avoidance swap (and i'd take the boots of the iron army over them any day if you can do 10man firefighter).
Generally speaking the "BiS" tanking set for really heavy hitters and encounters where threat isn't too tight is well below hit cap. Even with a complete wish-list of hardmode gear i'd still be a good deal below 8% in an effective health set.
As a tank you should aim to have a set like this as well as one that is hit/exp capped. Swapping gear between the two as you feel is necessary to both survive and retain aggro on the boss is half the battle.