YnngallerY

Honestly the thing I'd change the most is to have Ji-ung stick to her the whole time after that ordeal. Move the digging up his mom's remnants for a later day and have him be at her side when she wakes up at the hospital, hug her and cry a little about how he thought he'd lost her and how sorry he was not to have been able to keep his promise and why oh why didn't she trust him with her secret. It would have been a lot more poignant to have that conversation in the moment, while emotions are raw, than how it was actually done (which just made him sound manipulative and guilt-trippy when he'd been so good at respecting her boundaries before). And have Mi-jin confess that she was in way over her head and scared to lose him if he knew her secret and just dug herself too deep with the lies and didn't know how to get out of it.

Have them have the emotional conversation they desperately needed that way, and avoid that stupid "break up for an episode" trope that's so common to romance dramas' final episodes. Writers, if you want to sell us on a couple, actually build that couple's connection.

Then she could have been there with him when the police dug the skeletons out of the murderer's backyard, and they could have supported each other through it.

Also, we could have had a cute montage on them going on dates with her as her older self. I can't believe that never happened...