Your numbers sound about right. Using VERY ROUGH math - you should be doing over 1/3 the damage of the DPS. (Because most of your damage is increased 3x by your RF)
So - when you hit 25 man content the top DPS'ers should be hitting 5k+
In order to cover that (From a threat perspective) you need to be hovering in the 2k range.
Why you jumped on the actual boss fight is because KT is an extremely easy fight to tank. You should NEVER get frozen. You might have to move once or twice, but not much more. You should basically be spaming your 696 (Or whatever you use). You are getting Constant heals - so your mana is topped off. And it's a long time... Just stand there and spam.
Bosses like, let's say Gluth require you to stop, run, kill Chow. Or The Dance - is terrible for melee (Particularly Paly) Or what about Anub - Boss, Hit by spikes, run back to boss, Adds pop, run to adds.... Etc.
There is no time wasted on KT. Just that simple.