>make the game purely rally based.
>create your own liveries.
>all of the latest WRC cars and some older WRC cars such as focuses and imprezas etc and also the proper rally classics( mk1 & mk2 escorts, Opel manta etc.).
>rally career mode (start in 1.0 cars and work your way to the top maybe?).
>realistic stages (especially British stages and rally's such as Wales rally GB. Would love to be able to play on stages that look and feel like my local stages!).
>a British co-driver instead of American!
>make the game for next gen (especially PS4!).
>in career you should have a garage that you can walk around and look at your cars
>more spectators and marshals on the stages (it's the little details like this that make it more realistic).
>make night stages again.
>give the cars realistic sounds.
>this is a longshot but maybe drive between the stages?!(road sections).
>make a service park where you can change the setup and prepare your car for the stages
>ditch the gymkhana stuff.
>more choices of interior view cameras.
Sorry for going on but these are the things I think of when imaging what the best rally game would be like!!
:D