Oh god I forgot about the walnut....

Dash illumination would probably be the first thing I'd change, sad I know but I hate Green in modern cars, also not a fan of amber either. My daily has a fantastic dash at night but its ruined by old man amber!
Regardless of what I've said so far, the Octavia is a fantastic car and there's a lot of it for your money. There are differences from a golf that I am personally not keen on but that doesn't make it a lesser car overall. As I've said before, it depends what you want from a car.