I would not dispute that there is some skill involved in managing slice and dice. I would dispute that it's a good ability, though. Upping someone's passive damage over time really isn't especially interesting.
It's a bit like the argument that Killing Spree is good because it takes judgement to know how to use it so it won't kill you. That's true, and tactical, but also extremely bad design.
Surely they can make tactical decisions that are actually tied into abilities that are fun to use.
I'm a lot happier with rogues "passive damage" than most rogues so I like S&D being baked in and don't want it removed.