Infraction: 2. All opinions should be stated as succinctly as possible.
Message to User:
In the future, please just edit your post to add additional information rather than double posting. Thanks.
Now that I am re-reading your post, I think what you meant by a 1 second cast is actually a 1 second GCD. If so, then I see what your saying.
Here is the original post where it was deemed best to not delay CS for a filler.
There are also a few other posts from people that basically confirm this in later months when the question was asked again. That is why I think most people were under the impression that it was better to not use fillers.
Personally, I use the CSx3 - TV priority, however if I get an AoW proc, I will use Exo in the very small window that CS is still on cooldown, which works out very nicely due to the 1sec gcd on Exo.