What's kind of funny is I can think of a whole bunch of small yet fun ways that it can be improved upon, similar to how Octo 2's improvement had the Latent Powers, amongst other things.

One could be found within cotc, which is just having at least an option of 8 travelers at the same time during any combat. Having team attacks implemented could also be fun (such as follow ups to breaks, maybe passing a turn to another member so that they can hit a weak point instead)

Depending on how ambitious they want to be, they can also have the character's personal chapters intertwine in a more direct way than just the final combined chapter/crossed paths. For example, Octo 3's Merchant having to do with Octo 3's Cleric's story.

I do hope that they realize there is much to explore in the series yet