But for those who do not win a seat in parliament, what are they supposed to do, sit around in the visitors gallery and watch the debate?
Yup, sounds fun to me.
And why did the framers of this sim pick South America? We all know the U.S. in depth, but I would venture to say few participants have much of a knowledge of South America, other than it is that big continent down south, and has a history of two bit dictators.
As Barnes said, we already have a US election sim. It's not in very good shape, but if you want to try introduce a parliamentary system there you should go ahead.
I don't understand your first complaint - how is that a problem? We're not going to add meaningless and low-activity regional governments. All they do in Atlasia is act as a boring stepping stone to higher office. Start a newspaper. Yell abuse from the gallery. Do some analysis. Become a lawyer once we've set up the courts. Try to get into Parliament next time.