I know this is an incredibly unpopular opinion, but I preferred this season to the last. LET ME EXPLAIN!

One thing I will say is that I loved Jung So Min's portrayal of Naksu/Mudeok in Season 1, but I also really enjoyed the Season 2 portrayal, which reminded me of a Rapunzel-esque character who is locked away with no memories and thus kept childlike/innocent. I think the new female lead portrayed that pretty well. So this was not a major point of contention for me.

Regarding the other actors, I think Arin improved a lot, especially in portraying Jin Cho Yeon's forced maturing and JinYoWon's closing to outsiders. Jang Uk's portrayal was also really great, describing how Naksu's death impacted him and guided his character growth.

Personally, I prefer shorter drama, and the 20 episodes to me felt like it dragged on for a bit, so I for sure preferred the 10 episodes instead.

However, I will also argue that I am mildly put off and confused by the explanation of Jin BuYeon and Naksu's identity. Like from my understanding:
Bodies - Mudeok, Jin BuYeon
Souls - Mudeok, Naksu, Jin BuYeon

I am confused about whether Jin Buyeon's body was already inhabited by Naksu from the beginning or whether Naksu is JinBuyeon.