Great post. Couple of observations - firstly how shit was the quality of video in the early days. It's hard to believe we ever put up with that.
Secondly though the difference between the garden of BB1 and the C9 era is just really telling. They did everything they could back in BB1 to make it not look like a set, whilst in the later series it's as if they did everything they could to make it not look like a garden. That's not just a Channel 9 observation - it's pretty much the case around the world, and although there are other reasons the show lost it's innocence over the years there is a lot to be said for making the house as homely as possible so the housemates do feel like they're living at home rather than on a TV set.
I also still love the Square and Circle house and 16 years on do not think that twist has ever been bettered. That was when I really stood up and took notice of BB Aus, and that twist was so ambitious no country has ever tried to repeat the concept of having a house that begins as two houses and then merges as one. Although a few have begun with two houses they've all basically merged by moving the HMs into one of the original houses.