I know we are getting GT3 and GT4, which is fine and I will enjoy (just hope we get more than one or two makes in each class). What I think would be awesome for Reiza, since having obscure stuff is kind of their thing, is to have the Super GT license. The GT500 and GT300 (essentially GT3's) would be a nice get and no other sim really has them out side of I think one car in Rf2. Having the other Japanese tracks would be great too.
SuperGT licence would be very expensive I believe. Hence no-one ever has it.
re: GTs, expect somewhere between 2 and 4 cars (BMW, Mercedes, Porsche and one other), so another class without huge depth to it but at least this one will have some variation: