Same as I've had in the past.
Fantastical options
Let us change human ears to elf years? Or have mutated arms like Oprah? Or maybe a robotic arm like Yoshimitsu? Hell, why not let us create our own lizardmen and golems? Give us the voice options for our character to be completely silent, or give hisses/roars. Let us set our eyes to glow like Nightmare.
Facial hair editor
SCV tied facial hair to the face options, well no longer! SCVI should have a separate facial hair editor, complete with mustaches, beards, and goatees of every type. No more using tails or other objects to improvise a mustache!
In-depth face editor
Speaking of which, having to choose between a pre-set number of faces with no other options has to go. Every game with customization nowadays has an in-depth face editor, time for SC to join the club.
More creation slots
With the power of current gen, our creations shouldn't be limited to just 50 slots. I would like at least 300, so our creativity can flow.
More equipment
One of the things that bugs me the most is that LS has a ton of equipment that SCV doesn't have (even if a lot of them are barely-there slut costumes). Make sure to have more equipment in SCVI so we aren't limited without DLC like in SCV. Also, have everyone's costume be available has equipment without DLC, though it should be made an unlockable. Also, more anachronistic clothing too.