It's definitely a different seat due to all of the fancy massaging functions but I'm fairly certain it's the same size as my 2016, the bottom part is fairly small I'll agree with that. I'm a small guy so it's perfect for me, but I can definitely see how taller folks would be annoyed by the lack of thigh support they may have.
As far as the cavity where the pedals are, I don't see why that would be any different?