I personally want to see a really badass Naksu. Just like the one we saw in the intro of season 1. 

I know a lot of people aren't aboard with this, but I would personally like to see both JSM and GYJ in season 2 together. I want GYJ as Naksu and JSM as Bu Yeon. Bu Yeon has been hinted to be really powerful in season 1 and I would like to see that in season 2. And no, I do not want a love triangle with these two and Jang Uk. 

This leads to my second point, I hope they finish off the love triangle? Square? Whatever it is, I would like to see Jang Uk and Naksu in season 2 together. I would prefer of the story shifts to Naksu taking her revenge and Jang Uk and Naksu finding a resolution to this whole AoS fiasco. 

1- I would like to see Cho YEon "Naksu" taking revenge for her father's death ( still to be determined which soul was in Cho Chun at the time of his physical death) - and this will have so much plot to unfold as we still don't know how Cho Chun got his soul swapped and why and by whom...

2-Bu Yeaon "Mudeok" back ot her Jin family showing her true potential  and help UK and Cho Yeon in saving the world 😁😋🤗🤨

3- and of course some romance : i hope the main  triangle/square won't be dragged to S2 and perhaps S2 could also help the other characters to define their own one ( CP , Yul, Park jin, MAster Lee... they all deserve one 😍😘🥰😚😋😛