Spec needs a little TLC. Reckoning is a bottom-of-the-barrel threat talent, I would put those points in DS/DG for the extra utility (very useful cooldown as well as a small buff to your Sacred Shield).
You need 2/2 Judgements of the Just and 2/2 Vindication. Both of these are crucial damage reduction talents - JotJ should be self-explanatory, but Vindication isn't so obvious. It has a fantastic uptime, and the 574 AP reduction actually adds up to a tremendous amount of damage reduction because raid bosses scale with AP much much more than players do.
Also, Seal of Command is OK to spec into for heroics or whatever, but useless for raid bosses. Likewise, the glyph is not something a raider should have - replace it with the Seal of Vengeance glyph and enjoy your free 10 expertise. If you insist on keeping SoC (it's not very useful for raiding but all you're losing is 1% crit from Conviction, not the end of the world), I would use this spec.
Now for your gear. Get ready now, your gems and enchants need more stamina and armor. Most tanks entirely skip socket bonuses unless they provide +9 stamina or more, and some go so far as to ignore every single socket bonus except for the one purple agi/stam gem they need to activate their meta. There is no reason for a raider to use a pure dodge gem, nor a reason for a raiding tank to use a pure hit gem. You are gemming a lot of strength and hit, which is unnecessary. I wouldn't worry too much about the hit cap. If you find yourself hurting for threat, replace your dodge libram with the strength one.
Replace your shoulder enchant with the PvP one (30 stam), gloves with Armsman (if you need the threat) or 240 armor or +18 stamina, boots with +22 stamina, and shield with +18 stamina.
Your gear itself is pretty nice. Just fix your spec and enchants and you'll be ready to rock the place.