with my 11k/11k warrior I am sure I am not the best choice for Heroics. I am wondering when you began doin kara/heroics at as a primary tank with your warriors?
It really depends on your group and the heroic. I didn't start tanking heroics untill I had the felsteel set and 2 pieces of the bold set. But with a good group I have run on my shammy with a tank in mostly greens with no issues. Not a pug but a guildies tank alt. As long as you have atleast 490 def and 11.5k hp you should be able to tank most heroics assuming you arn't 3 and 4 tanking. But 1 or 2 you should be fine. But if its a low dps/cc group you will need to be a bit more geared. Try heroic mech it's 1 of the easiest and there is a shot at the sun eater or the pants for an off set. I just got finished a Hero BM run with a tank that has about your stats no issue.
I agree with the above. If you have everything you need from normal instances, then it is time to do heroics. Just make sure you have a good healer. Those bastards hit really hard compared to normal instances.