hardcore mode, new skills and rebalancing, wands, dual wielding, and perhaps throwing weapons
Well, all of those are perhapses, really, though I think hardcore mode and dual wielding are pretty much guaranteed. I call it "hardcore mode" because one of the official modding documents names "hardcore mode," and seems to imply that certain enemies will spawn when this mode is active. This makes me think that you won't be able to switch to lower difficulties midgame, but I could be wrong on that. I also suspect throwing weapons because of another hint in the same document that the "throwing" skill (along with DW and wand use) is "not yet implemented." I don't know exactly what "throwing" implies; could mean throwing potions, or throwing axes and javelins, or perhaps you can throw your enemies, but my best guess is it's another weapon skill.
It has been a month and a half since the last update, so I would expect it to have quite a bit of content, but we'll see.