I agree with the above comments about a shot rotation and using Aimed Shot.
For a good illustrated example of shot rotations and why Aimed Shot isn't good to use in a rotation
see this link.
Your explanation of using Aimed Shot when FD is on cooldown and using the cast time of Aimed to not generate agrro doesn't really make sense. True, you may not be getting more aggro during the cast, but Aimed Shot should have the potential to be your single biggest damage shot. So, although you may not be getting aggro during cast time, that's negated if you get a huge crit when it fires. When I'm in that situation, I typically revert to only using Auto Shot until FD cooldown is up. I usually don't let myself get too close on aggro anyway. If I'm climbing the charts too quickly, I just pop FD. It's only a 30 sec cooldown and in a raid I'm much less concerned about using it to save me a death as I am using it to manage my aggro. If you're risking grabbing aggro again before 30 sec is up, the tank needs some help.
The other thing to consider using is Scorpid Sting. It's a bit of a mana hog, but the 5% hit reduction makes other raid members (particularly melee) very happy.
Another I notice is that you don't seem to be using Aspect of the Hawk. In my opinion, hunters should have Hawk up most of the time in raids. Use consumables to refresh your mana during a fight. Unless you're almost completely out of mana and pot cooldown isn't up, then use Viper. But, otherwise, you're just sacrificing AP.
Overall though, these are just minor tweaks. It looks like you're doing a really good job as it is.