Basically as the title says, I went into DS the first time yesterday and I got hit very hard to the point to where I was popping all my cooldowns only to delay my inevitable death due to me taking so much damage. holding back my group from killing bosses.(Mind you I was dieing to Morchok, Zon'ozz and Yashi'jerj) After leaving the group and looking into what I may be doing wrong I couldnt find anything. Can you guys see something that I am missing in terms of gemming, enchanting, and reforging?
I also had a hit cap question. I understand that hit and expertise are redundent now with the vengeance change. But my hit rating is so low that I miss demoralizing shouts and Thunder claps regularly. Any adivce on that?
Your gemming is a mess. Very wierd to see an expertise/mastery gem ('fine' parry+mastery in red sockets is better), or to have green gems in prismatic (or red) sockets. You are missing enchants on your gloves (mastery or greater mastery) and bracer (dodge). You've made some seemingly strange choices with your valor purchases (the cloak is really good, the thrown not much better than the quest reward from the new instances).
Overall, it looks like you are unclear what you are trying to achieve with your gearing. You should read around on "Combat Table Coverage" or 'CTC' on this site, there are plenty of threads on the topic of ensuring you have enough mastery to at least block (if not dodge/parry/miss) every boss swing. Most warriors aim to be at or near full CTC in this tier of gear. If you understand what that is, and instead choose to go the stamina root then that's your decision - but at least be consistant.
But. The first few bosses in normal mode really aren't that tough, so it's also highly likely that you are also doing the fights wrong. On Morchok, that means 2 tanks taunting off each other before their debuff goes too high. On Yor'sahj, that means switching tanks when void bolt stacks high (and you might consider breaking out the baradin hold mirror trinket for that). Zon'ozz does hit fairly hard, gear will be a factor here, but so will smart use of cooldowns as his damage ramps up. It's his big frontal 'psychic drain' that is the killer, so try to have some kind of cooldown up for that when he is getting hurty. If you understand the fights and make good use of your active cooldowns in response to the mechanics, you will increase your survival significantly.
Grab yourself the VP trinket to replace that stamina one, and gem for more mastery. Red = mastery/parry, Blue = stam/mastery, Yellow = straight mastery. If a piece of gear has no mastery on it, reforge the highest stat to mastery. You want to get about 14-15% more block chance. At the same time, your health pool is low, so you really want to work on getting upgrades from HoT heroics and VP. Do BH and LFR every lockout as well. You're missing dodge to bracer and mastery to gloves, and should either enchant mastery or lavawalker to boots.
You logged out in PVP gear, so i'm going to assume ^^they^^ caught everything that's really important. Just real quick as a matter of nitpickiness, take 2 talent points out of either Imp Rev or Thunderstruck and finish filling out Incite and Deep Wounds. I believe the majority of the community prefers thunderstruck over imp rev, some may argue the opposite. Really, i'd say pick the one that fits better with your play-stile/rotation.