How are people defining flop because I see 3 ways to look at it
1. Below expectations - By this definition I think it will be a flop
2. Will cost Disney more money then it will make - I very much doubt it will be a flop by this definition. They wont make the amount of profit they wanted but I still think it going to end up in the green for Disney.
3. Lost of potential Money (IE by releasing this movie you devaluing the star war franchise as whole) - This is much harder to prove one way or the other. Will merchandise or sales of future movies be less then it would be if they never released this movie. I personally don't think it will be a flop by this definition. People that would be turned off from Disney star wars because of this movie have already been so after last jedi and this movie wont make anything worse for Disney.
Personally I came into the movie with low expectation and it did beat my expectation. Was not a great movie but was entertaining enough and I have no regrets going to the movies to see it. Also people making way to big deal about Lando.
Spoiler ahead
If I had gone into the movie without reading anything before hand, I would had thought it was meant to be funny (a joke) that the robot thought Londo was in love with her. Also when the robot was killed that he was just upset about loosing a friend. The whole Pansexual thing would not even had occurred to me.