You aren't supposed to be able to tank all of Karazhan including Prince and Nightbane the first time you go in there. That's the whole point of progression. Not saying it can't be done. But that's not how the loot tables are designed.
Looking at your armory, I'm sure you COULD tank everything given the correct group. There's a lot of possible upgrades to give you a better shot though.
Well that's not a problem then, because i don't think i lie if i say i've done 30 full karazhan runs. I have a t6 rogue and a karageared hunter, so I know the fights very well.
My only concern is Nightbane and Prince, as i know they can do some heavy damage at times. So i ask you, do you think that i could manage to tank them with my current gear? And what upgrades would you recommend to it?
I agree with leytur, get sso rep for shield and neck. Nightbane you should be fine, that is not a prticularly hard fight, just 2 things to win it, stance dance and don't stand in the fire. Prince I think you are on teh edge of being able to handle it, your stam right now is a little over 2 back to back smacks killing you. Bring plenty of stoneshield pots, nightmare seeds, moroes watch if you already have it. You are going to ride the line but with a good group I think you could down him.