I feel like this was a short game and the only thing that made it long was all the cutscenes. I hear about people already being at The World That Never Was at levels 18-22 which is way too low. Other than that, I agree with the above complaints. Plotwise, I feel like the entire plot of the game didn't happen until the last world which seemed to make the first 6 pointless.
But, with all those complains in mind, which are really minor, I thought this game was great and is still one of the best available on the 3DS. Best in the series? Close, but I'd have to think about it more since Birth by Sleep holds that title for me.