Decided to give this a go on my lunch break. The only change seems to be the mist form other players (think the blue dots from Southsun Survival).
First successful completion gave me an Exotic Mad King’s Chest, a Spooky Skeleton Tonic and a Spooky Ghost Tonic.
Opening the Mad King’s Chest presented me with the option to receive Account Bound/Soulbound on Use Exotic gloves (Light, Medium, or Heavy). You get to choose the stats, and they come with a Superior Rune of the Mad King.
Subsequent completions on the same character seem to only grant 4 Trick or Treat Bags. I have yet to try out a second character.
Edit: Ran a second character through and only got the Trick or Treat Bags so it appears rewards are account bound. Therefore, rewards are worse than last year as it was possible to get the Boots on each character.
