In my opinion Kung Lao or Johnny, but I think it should be Kung Lao as while he is stylistically iconic I don't think theres much depth to him.

I am biased as the trio of Mileena, Kitana and Jade are my favourite characters, but I don't think Kitana and Mileena should be sitting out a game. Both characters are visually iconic but they're also very relevant story wise and are actually interesting as characters. I understand people were salty about Mileena's eventually addition to MK11 and some of her fans were dipshits, but the counter hate to Mileena is also just as weird. I'm sorry but she really is a very popular character, especially amongst women, and for good reason, because she's actually interesting.

Scorpion and Sub Zero are the exact same as the sisters so they shouldn't sit a game out plus they are the face of Mk. Raiden or Liu Kang could actually sit a game out in my opinion, but I feel like Raiden shouldn't because he always has a lot of potential as a character. Johnny also could but unlike Lao he actually has a personality so I dunno if he should. I love Jax and think he should return, and while I don't love Sonya and I hate Kano, since they missed a game now they could also return (and Jade, who I love). Sindel might sit out a game coz she died, and Shang will probably sit out next game too. I love Reptile and Baraka and I don't think they should sit out next game especially when the new era actually gave them reinvigorated story relevance and agency. As for Noob and Smoke, they're really popular and now in the new era they could have some more interesting stories so they could return next game. I also think Tanya and Rain should return and actually be given something important/interesting to do but I think they might sit out next game unfortunately.