I personally feel swapping one of the sleeps or the stealth power for something like "poison caltrops - caltrops coated in a paralytic poison, functions same as normal caltrops with a minor toxic dot. The first instance of damage enemies recieve from them has a chance for a short immobilize. It would allow some containment interactions, a tiny damage boost plus the animations are already in game so very simple to implement and still works thematically. I know the set would be heavy on placeable aoe powers but that can then be the sets "playstyle"
I've played cox since issue 1 and sleeps are wholesale the only power type I have consistently skipped in every power set they are available in, I've never found them useful beyond niche 1 in a 1000 circumstance so having to choose between 2 at the start feels bad but I'm probably just biased here 😂