Well, finally finished with all characters on the Octopath Traveler demo. Two things I want to mention. I seemed to have run into a bug while playing the Archer/Hunter/Pokemon Trainer. She starts in a heavily wooded area with a bunch of foreground trees. Most of the time the opacity on these was 0% making it really god damned annoying to move around when I couldn't see a damned thing. Did anyone else get that? I also feel that her battle mechanic will be overly cumbersome unless you know exactly what to capture.
Second, my god. I did a run where I recruited a third characters in one go and the boss for the third recruit had a stupid amount of health. It took me like four times longer to kill the damned boss because of its increased health. It wasn't really any more difficult, just more annoying by how much extra health it had. Especially when compared to the boss I took on for the second party members story where I had two characters. I dread how much health a boss will have when you have four people in your party.
I didn't remember the Huntress' forest section hard to navigate. And I think her capture mechanic isn't really crucial. Seems like it provides more attack types to fill in gaps from your party.
As for the boss scaling, it was a fair difficulty spike. You get another member to break and boost. Also, later skills and passives seems to synergize pretty well with certain parties.