Just bring back the various ISI-Tracks!
Mills Metropark (which according to ISI had kept good funding, and been upgraded, looking posh).
Toban Raceway (Which according to ISI had not had any funding,with worn-down buildings, cracked tarmac etc.)
Sardian Heights, the city-track from rF1
Lienz from rF1, because we need a RX-style thing, windy roads and cobblestone!
Chatham from Sports Car GT. The short road-track with half and oval, without being an oval. That downhill braking after the loooong banked first corner was epic!
North Point from Sports Car GT. A more traditional racetrack, with elevation changes.
Sardian Park from Sports Car GT, I guess it was in the same fictional city as Sardian Heights, but this was a "park" track. With an extremely wide first chicane, and the track then narrowed down to a really interesting track with loads of elevation changes. Technical, tricky and narrow!
Bring it on!