Tricky decision for me personally.
MK11 will be the first fighting game for me personally, where I'll try to actually git gud and into the genre for real. Since MVC3 and MK9 I was only watching tournaments and button mashing. So I know what fundamentals are, but I don't have them.
My favorite MK characters are Smoke, Noob Saibot, Rain and Sektor. Right now I only have Noob, so I will be playing Noob.
I still have to be careful to not develop bad habits with Noob (for example spamming clones all day long and dropping dead as soon as someone gets in), if he happens to be such a character. So I might end up playing characters like Kabal and Jade more than I would have wanted, just to develop better fundamentals: Footsies, decision making, reactions, execution etc..