Only if you can use them on the boss. Which i doubt will happen since that means you will be required to bring a rogue. And all of the standard poisons affects can be performed at range by another class or a tank.
Because boss fights never involve adds susceptible to CC.
At the rate things are going, I'd anticipate getting -more- encounters where these sorts of abilities would be extremely useful in the future. Which is potentially why they're being given to us now.
So, again. Until we see what the beta has in store for us, it's pointless calling any of this worthless.
How is it pointless pointing out how I see this panning out with the current information I have? Just because you are an eternal optimist always destined for disappointment does not mean I am too. I prefer to be pleasantly surprised rather than always disappointed. I share your hope in that these abilitys will actually be useful but history of the rogue class tends to indicate otherwise, we aer still using the same rotation as in vanilla and we are rarely if ever called apon to do anything other than stay alive and dps with the occasional kick or feint.
As it stands I see limited or no benefit from any of these poisons in a raid environment other than leeching and I hope that something is done to change that. Lack of information to support your optimism does not mean I should assume the best, actually if human history is anything to go by it is more logical to assume the worst. People don't do anything unless they actually see a problem and if no one points at the giant pink elephant in the room it is rare that anyone will see it fare less do anything about it.
Oh and name me 1 fight where a melee CC is better than anything that a range can bring? Even with these shiv abilities none of them offer any range CC or anything that a rogue can do better than any other class. In most cases they would be the least desirable version. if the reverse was true we will see a must bring rogue situation which is unlikely to happen.