The first thing to note, and this applies to all tanks, is that a tanks main damage source is the amount of vengeance they can accumulate. When you are sitting on nearly one million attack power you are going to be top dps without even knowing correct rotations and what not. If you want to do good damage as a tank, then learn your limits, learn how much you can abuse yourself without dying. Learn the mechanics inside and out and learn what extra damage you can take for vengeance without dying. For example on fallen protectors I purposely receive the armor debuff just so I take more damage as I overgear that fight quite a lot. On a fight like Iron Juggernaut you can switch at 6 flame vents stacks instead of 3, and if you are feeling up to it and have the gear can just fully tank the boss and receive all 12 stacks before going into siege mode, although I have never seen anyone do this in a 10man raid so I would suggest it right now But lets talk about your paladin in particular ^^
You should basically running Glyph of the Alabaster Shield in every fight if the first thing I noticed, might aswell use your empty glyph slot and its probably one of the best for increasing your damage
I know a lot of prot paladins use Holy Prism in 10 man raids, but you will rarely get a chance to use it on cooldown as other things should be coming before it in priority and if you can not use it on cooldown it falls even further behind the other two talents, I normally just stick with Execution Sentence for every fight but I'm lazy and never change it
Your ability priority seems a little strange to me, from both a dps and survivability point of view you should always be using CS and Judge at a higher prio as it will stop the GCD gaps I bet you are getting, and will also let you use Shield of the Righteous more often, which does do a fair bit of damage and because you are using Divine Purpose will also give you more chances to proc it to do even more damage.
If you are only getting hit by one target then your rotation should be CS > Judge > Avenger Shield (with or without proc doesnt effect its position) > Holy Wrath > Hammer of Wrath > Consecration.
This is because the goal is to generate as much holy power as possible, and delaying your CS and Judge by one second is a holy power loss as it is unlikely your Grand Crusader is going to proc in the ~2.5 seconds it takes you to use both CS and Judge. However if it is procing more then once every 2.5 seconds, as in you are tanking like 10 adds, then just spam that shield away
On AoE areas, your prio should be:
Hammer of the Righteous > Consecration/AS (depends on proc rate) > Judge > Holy Wrath > Hammer of Wrath.
However as you have moved judge down the list you are sacrificing survival to do more damage, if you need to you can move Judgement further up the list in order to generate more holy power.
Your tier 6 talent will also be included in there but in varies alot on the fight, which talent you took, vengeance levels and what else is going on, use your own judgement on it but it should *always* be after your Holy Power generators and normally after Holy Wrath too.
On your Immersus kill you didn't use Avenger Shield until nearly 12 seconds into the fight, when really it could be about ~2 seconds, and this is your hardest hitting ability. Instead you used Consecration, which ironically is your weakest hitting ability on single target. Also, keep in mind that all the time its off cooldown, if it procs you waste the "reset cooldown" part of your Grand Crusader, but keep in mind what I said earlier about CS and Judge first
In terms of gear you should be going for 50% haste unbuffed then mastery for survivability, or crit if you don't care about dying or not
Haste is both a damage and survival increase. Mastery is just survival. Crit is just damage. Choose what you want to build but as you are progressing I would suggest you go with the standard Haste>Mastery. Once you can clear all your content without worrying about deaths you can start reforging your mastery to crit just to do more deeps ^^
Maybe you have been unlucky with loot, but get Thok's Tail Tip ASAP.
Anyway good luck with your prot paladin tanking.
P.S If it makes you feel better, currently in WoD beta prot paladins do A LOT of damage, to the point that even with vengeance being removed you can still do 40-50% of the damage in a dungeon Pls no nerfarino (