If you loved the original Octopath Traveller, you'll be head over heels for this entry in the series, as almost every element of the game play has been improved.
It is quicker to list what hasn't changed first: mini-map is still a radar; you get 5 strikes for reputation in each town but no obvious indicator of it's level when you re-enter a town; the camera angle is fixed making it hard to find entrances to certain paths; the deity pantheon is still the same.

Improvements:
improved weapon selection, plus the weapon artwork changes to represent the equipped weapon when striking.
more hidden entrances - dungeons & shrines might have an entry point that is not directly visible, requiring you to explore more.
bodies of water (streams & open sea) - allow for more aquatic enemies and more complex paths to reach selected locations.
day/night cycle (~8 minutes between changes) - influences monster selection, which path action a character performs (they have 2 each) and which NPCs are available and where they are in some cases.
Job skill sets have been re-vamped, some more than others; each hero can unlock 2 unique skills for their job ; up to 3 heroes may now have the same secondary job. Advanced jobs have been changed - 4 new skill sets, however not every one requires a drawn out boss fight to acquire it - first one can be stumbled upon in the first few hours if you select the right start location (east continent).
Some path actions have been improved: captured monsters can become food, dancer & merchant hirelings can provide extra assistance. the warrior can learn extra skills from duels.
Stories are now more diverse - it is no longer visit 4 dungeons in sequence and defeat the boss therein. Stories can have more than one route; some chapters will require both path actions to progress the story with the merchant's story requiring you to spend sizeable amounts of money.

The only story I felt no connection with was the Dancer (Agnea) - wanting to be a star.

It's so good I bought it twice

Combat is entertaining and overall the game is pretty fun to play. It's really cozy and "warm", thanks to the pretty visuals and great soundtrack. Boss fights are cool, they are designed nicely and usually feature some interesting gimmicks.

But I must say that the characters' stories are pretty bad. They start okay but quickly devolve into very childish and tropey storytelling with maniacally laughing moustache-twirling villains. You'll get every possible anime cliche there is and I swear to god some of the main characters are so morally good it's puke inducing (At least we get Throne to balance them out). I won't even address the amount of stupid stuff happening during some of the stories where logic goes out of the window completely.

And there's a problem of having 8 characters in your team but you barely see them together. Every character's main quest's scenes only feature this character and none of the other party members. At least there are some small scenes you can trigger during main missions where your party members talk to each other, but unfortunately they are not voiced.

Despite all that I had fun playing this.