For me, theme, color and detail are the most important elements in good character design. My characters often present a futuristic military or historical (Victorian/WWI) aesthetic, though I also enjoy having fun with drastically altering the appearance of canonical characters. I always try to use items, stickers and patterns in unexpected -or even unintended ways. I design exclusively on the PS4.
I prefer the smooth stylish minimalism in character creation - when the work looks solid and complete as if it was created by the game developers themselves. But sometime, especially for cosplay, you need to add untidy detail to simulate any stuff, that was not included in ingame base.
Since I remember, I spend a lot of time designing characters in every character creator I ever got my hands on. So its natural that a fighting game that has a big focus on character creation would be one of my favorites (and 2/3 of my time in-game would go on creations). Mains Voldo and Astaroth.