It's the most useful skill for warrior since they can't run fast or attack from range and when a rogue runs that's pretty much it you ain't gona catch him unless he wants to continue fighting you. Since so many people have high resis you need to balance it so it will work. At least 1/20 chance of slow down is good enough. Out the of whole time i play on this server (2 months) only slowed 1 person with scream.

I think someone posted on this fourm awhile ago that current rate was 1/60 for scream

It' actually a tiny bit higher now then when I started, but still horrible a rate. As I undersatnd it, they may be "considering" some changes about that as we speak. We will see.

p.s. everyone feels the same about war LC/Scream rates