Right now, the new art looks incredible, and the lesser number of containers probably makes a much nicer learning curve, and looks less intimidating. However, with each container less the number of potential answers goes down exponentially, and I wonder if the smaller number might end up hurting the gameplay at the higher levels.
Because of that, I think that maybe the game could use a mode where it switches to six. I assume the current art can't accommodate that, but since it is already drawn and this is a minor change to existing assets, it might be possible for even a relative non-artist to modify and make slightly shorter containers and some new pipes for this purpose.
https://github.com/kyung01/xo-fractions-game/issues/23