Post by Selina
Your equipment looks mostly okay for Karazhan, but you wear a lot of low armour items so you might need some additional armour. I would suggest that you check this
list for possible upgrades.
As far as defense rating goes you don't need anymore. Actually you seem to be above what is needed, because your gladiator items afford you 73 resilience which works towards your crit immunity just like defense.
Actually I think you can consider regemming those defense rating gems for something more worthwhile. (Either agility/hit or stamina.) Use this macro to check whether you are crit immune (and how much you are above the cap):
/script DEFAULT_CHAT_FRAME:AddMessage(2.6-(GetCombatRatingBonus(CR_DEFENSE_SKILL)*.04+GetCombatRatingBonus(CR_CRIT_TAKEN_MELEE) ),1,0.5,0)
If the value is zero you are immune to crits from boss mobs. If the value positve you can be critted. If it is negative you actually have more defense/resilience than you need for immunity. (This assumes that you have survival of the fittest 3/3 which you have)
Hope this helps.