will have to give it a go and see what difference it makes, my main concern is trying to be that dependant aimed shot is going to be hard when you are dodging stuff in raids.
the other thing I noticed is a hot fix went out for focus regen not using the correct values giving too little so it is possible that may make it more possible to cast more and do more but will see after the restart next week since they claim it is needed.
also why is the base cast time of cobra and steady different? with 4.0.6 my cast time of cobra went down to the 1.4 area from 1.6 before the patch, but steady still seems to have quite a bit longer cast time. this is one of the reasons I ask the speed because my steady goes down to about 1.5 self buffed (near 1.4 with the 10% haste buff) and self buffed aimed is still at 2.3 self buffed so in a 16 second window of keeping up, your rotation would leave just over a second for reactions over the entire rotation making it seem like it would be near impossible in a dungeon without dropping the sting. so even with the 10% haste buff you are probably going to be pushing it in anything other than tank and spank fights.