Dishonored 2 [official site] is one of those games that I don't need to read about, because I've already decided that I'm going to play it based on how much I enjoyed the first's blend of magic and stealthy murder. Still, for you, I have mined Game Informer's recent preview for news of how its new and old powers will function.
Arkane's sequel starts two characters, one of whom is the hero of the original, Corvo Attano. For undisclosed reasons (videogames) Corvo has to re-gain all the powers he enjoyed during the first, though those abilities have been tweaked somewhat.
Blink is back, for example, but can now be upgraded to allow you to pause time when not moving, just as Daud could in the Knife of Dunwall DLC. Possession, which allows you to possess other humans and animals, can now be chained together so you can hop from entity to entity seamlessly and can be used to possess dead bodies. Devouring Swarm returns also - which is slightly more odd, given that the new city of Karnaca doesn't have a rat plague - but is now tempered in power somewhat by the introduction of bloodflies who attack rats "on sight".
The second character is Emily Kaldwin, daughter to the assassinated empress from the first game's opening moments. Her abilities are more interesting because they're brand new - although in some instances are an obvious mirror of Corvo's. For example, Far Reach is an obvious equivalent of Blink, letting you cover large distances quickly, but it's powered by a supernatural grappling hook and so you're visible as you travel instead of teleporting.
I'll leave the many other details to the Game Informer article, which you should go read. It's heartening - though not a surprise - that the non-lethal playstyle will be even better supported this time around. That's how I played the last game, though I gave it up when an event gave narrative motivation to do so.
Dishonored 2 is due on November 11.