In my opinion this sequel is a great continuation of the first Darkest Dungeon, the gameplay loop is different ofc but you can't always go wrong with changes.
I like the idea of a more traditional roguelite where you unlock stuff and use them in new runs i think it is a better adition than the first game where you progressed in a world not a run persay, i've seen people compain about the fact that the characters lost their appeal as they are now reset every run (except for the memories) I believe that this game does the same thing as the first in this case because if you really care about the characters try beating all the chapters with 4 of them from start to finish, I believe that is where the game really shines in making the players like their characters, and ofcourse when you do that you will have not only the memories remain betwinn chapters but their querks as well wich I believe makes them unique really.
When I played the beta of the game I thought it was dogsh** but now that changes have been made I believe the game is best it's ever been and with the addition of mods and the new game mode "Kingdoms" wich wants to bring back the clasic Darkest Dungeon experience that was the first game in the near future.
I believe this is a great game that should at least be tried and if you think its not for you, you can always refund.
Thank you for coming to my Ted talk. (Sorry for bad english)