There's a few tracks that IMO, was actually spoilt in GT4.
Trial Mountain and Apricot Hill Speedway comes to mind. Also, it's crazy how beautiful circuits like Deep Forest, Seattle, Apricot Hill, Midfield Raceway, barely organizes any races in GT4.
It's always the crappy ones like Test Course, Montegi, Tsukuba, Seoul, Tokyo, Hong Kong that hold races.