If you run with competent DPS then why bother going deep into Shaman? DPS is not the concern of Tanks, only threat and you said threat doesn't seem to be a problem for you. Here are some of my thoughts:
Justicar: You are missing 2 HUGE damage mitigation abilities not going at least 44 pts deep, Just Defense and Resplendent Embrace. IMHO the 51pt ability is meh unless you are having threat problems in AOE (which I don't even have that issue in my support DPS build, let alone my tank build, if I have Mein of Leadership up). Not going 5/5 in Safe Haven I'm on the fence about, mitigation is mitigation, but 2% isn't a ton either, and it's block rating anyhow. You took 2/2 Healer's Creed but didn't take the 1/1 Doctrine of Bliss or Valiance. If it's true you run with a competent healer then drop at least Healer's Creed altogether, but not having the single point Doctrine of Bliss (mine heals for ~500 without critting) or Valiance (I've seen mine crit for over 1k) is dodgy at best. You also didn't take the CC abilities which to this point I haven't seen mobs run away when near death so shouldn't be an issue.
Shaman: Vengeance of the Frozen Earth is 100% a PvP talent since like I said, mobs don't seem to run away. Unless you are using Shaman abilities in your rotation, Lust for Blood 3/3 will never get used. It will proc but does not get used with Justicar abilities, which you need to gain Conviction, which you need to use Doctines that you took 2/2 Healer's Creed to reduce mana usage of.
Going the route you took is also slightly gimping you in mitigation as a tank. You do not gain benefit from Protection of the Ancestors (you can only get 2/5 but that's still +20% shield) or the Shield of Oak if you had gone Druid instead of Purifier (which is arguably the worst of the 3 shields).
If you are doing fine due to your group makeup in Experts then by all means keep doing it, however I doubt this build would fair well tanking in Raid, just my opinion.
DPS: (Inq) 51 (Sent) 10 (Ward) 5
Raid Healer: (Puri) 32 (Sent) 34 (Ward) 0
MT Healer: (Puri) 51 (Sent) 15 (Ward) 0
Tank: (Just) 47 (Sham) 7 (Inq) 12
Inquisicar: (Inq) 51 (Justi) 14 (Sent) 1