This looks like a great tool, particularly the ground-up focus on threading and giving teams more options. As with its competitors, it can still easily become just another distraction when people use it wrong.
It's easy to see how you could design a "process" around using something like Slack to achieve the same experience and if you don't design a "process" for using Twist then it will suck just as much. We tried to heavily use channels in HipChat as a threading and noise-avoidance mechanism, it worked well but we often ended up with a lot of channels with the same people in; at which point discipline becomes stressed.
It's easy to see how you could design a "process" around using something like Slack to achieve the same experience and if you don't design a "process" for using Twist then it will suck just as much. We tried to heavily use channels in HipChat as a threading and noise-avoidance mechanism, it worked well but we often ended up with a lot of channels with the same people in; at which point discipline becomes stressed.