I've gotta be honest, I've been racing on those tracks for the best part of 20 years... I'm not that bothered about getting them. They were a product of racing game culture in the 90's and the limitations of the first Playstation (trees and tunnels everywhere!)... the nostalgia is strong with them, but if they were to come back I'd want a total overhaul of them, with more than one layout (in either direction), just something to make them feel a little different.
As for the update rumour itself...
I think it's reasonable to hope some additional content along with the Supra, and what Car suggests is reasonable if we accept that PD can continue the established previous pattern. 2 tracks could mean anything though, I wouldn't be getting my hopes up for new stuff, but Alsace, Dragon, and Fishermans ranch are all ripe for additional layouts. Every month they keep this pattern going for is a bonus as far as I'm concerned.