I'm most excited for a mortal release too. I like the idea of humans wanting to attain the vain grace of an elf, and seeing devotion to slaanesh as their only option.
Most of all, I want the philosophy of Slaaneshi faith to be developed , as it is easily the most rich vein to explore within the chaos pantheon.
I have my own headcanon for this:
Slaaneshi faith consist of three conflicting 'vice aspects' (thus 6 vices in total).
Submission and Dominion
Submission involves the desire to obliviate the self and give one's essence fully to Slaanesh. This aspect is for the masochists: the frenzied hellstriders and singleminded acolytes who only know devotion.
Then there are those spurred to dominate. This can be embodied either by a sadistic tyrant or by a benevolent patriarch: in both cases, pleasure is derived from controlling the fates of others.
Excess and Neophylia
Excess is perhaps the most commonly manifested aspect: the overpowering addiction to food, drink, sex or violence. It differs from Neophylia by being the obsession with a singular thing, while the Neophyle prizes novelty and interest: any diversion from monotony. These individuals become collectors and explorers, forever malcontent with what they have.
Vanity and Creativity
Any self respecting Slaaneshi devotee is somewhat vain. This vanity can manifest as the pursuit of aesthetic splendour, or in the pursuit of arcane/martial prowess. The inherent drive is to be the best , and to SHOW that you are the best.
The creative takes the same instinct for externalizing perfection but separates it from the self, and instead it manifests in the individual's art or craft.
I like this taxonomy, if only to argue with my friend that "pleasure " is actually a philosophically rich topic. There's just a lot more to do with Slaanesh than androgynous shiny bois.
Mage/artist hybrid character who is all about creating dazzling illusions, the batteries his canvas.
Mixed gender, portly warriors, striding into battle with sword and wine flask (gender representation is getting better at the moment, so let's have some fat ladies and gents).
A leviadon/stegadon style big beastie (some scaly insect horse thing) with a howdah housing a banquet of warriors, complete with a music band. Could alternate build as a library, a repository of forbidden secrets and deviant thoughts.
I could go on, but you get the point:)