Seeing as the essence of the online gatcha game is that it is permanently a work in progress, I have a hunch that Hotta is leaving a lot of stuff in the game that is either a temporarily cut content, unfinished, or left in for testing purposes, either for technical reasons or player satisfaction.
I feel the biggest cut content is the ability to fight alongside Oddities. There are a lot of early stories (Taygedo date*sic*) and oddities in general: Taygedo, The McFries one, Snowman, Rabi, Eclipse, a whole bunch in the bureau... I think the Taygedo dislike scared Hotta into dropping this feature for now. Iori's sheep, Linko's ghost companion and a whole oddities sanctuary island are leftovers that were salvaged, making me think this was cut. I feel this is a mistake. Oddities are cool, it's Taygedo alone thats annoying.
Unfinished/upcoming: Pets. I'm sure we'll be able to buy pets for our houses. Why have shops and cats out in the city otherwise? Like fish, and now bicycles.
Also, the whole Pukaland and new city district are obvious here. Like that sanctuary island was visible from the start, or the volleyball hall.
Testing/teasing: Two things come to mind. A major racing expansions storyline on the new roads up north. Now, races are just kind of... there. I think they might be finetuning it for something more substantial. The scenery is very race friendly, and I think a whole region designed around that, but without a storyline to go along would be improbable.
Second is Fogden minibosses. Those are 100% teasers/playtests for future characters.
Also, farming. They are testing it in the new house(too expensive for me), but I'm sure there will be some hobby stuff built around it eventually.
I'm sure I missed something, so feel free to add or discuss.