Gloves: Yes definitely get gauntlets of the kraken. Gem them with 2x30 stam gems and put on either the 18 stam or 240 armor to glove leatherworking enchant
Legs: DEFINITELY get Pillars of might made if you can, gem with 3x30 stam.
Wrists are fine, gem with a 30 stam gem though, don't waste time worrying about hit rating and only go for socket bonuses that are +9stam or higher that only require 1 hybrid gem.
Rings: Definitely pick up H-Band of the Twin Valks if you can, it is actually better than the ashen verdict ring, otherwise your ring selection is correct.
On to things you weren't asking about specifically:
Helm: Since you're over 26 expertise, unless you are having threat problems, I'd suggest changing this from a 10exp/15stam gem to a 10agi/15stam gem or a 10dodge/15stam gem.
Shoulders: i would suggest changing the enchant to the 30stam/15 resil PvP one (10k honor from the honor vendors in stormwind)
Chest: Regem with 3x30stam gems. Since this +12 socket bonus requires you to use 2 hybrid gems it is more like you are gemming for 2 +6stam bonuses and therefore you are losing a net of 18 stam by going for the bonus instead of just 3. Gear for EHP so gem all 3x30stam.
Weapon: Definitely change your enchant to blood draining, if you are going to be progressing and hitting content, it is a must, imo.
Boots: I'd change the hit/stam gem to either defense/stam or 30 stam. I also highly recommend changing your boot enchant to Tuskarr's Vitality. The movespeed is simply priceless
Belt: Again I'd suggest changing the exp/stam gem here to either agi/stam or dodge/stam (the difference being that agi gives slightly less dodge but also 20 armor)
Spec is exactly optimal, only thing I would change is moving 3 points in shield spec into focused rage, but that becomes more of a personal preference. Gylphs are alright, but make sure you are carrying around glyphs per situation, last stand and shield wall can be very good/important on some fights, expecially hardmodes. So basically you're still correct about glyphs, don't worry about it.
For your survivability spec, I'm not sure how I feel about taking points out of gag order and putting them into imp revenge. It's probably more overall damage but idk about how much overall threat. I also really like the utility of gag order, but on fights where you'll be using that spec I doubt gag order is that important. Idk... I think this is actually a very legitimate question. Definitely do not drop Tclap for it though. Your primary concern for a 5/15/51 spec is survivability, threat takes a back seat.