Would like it to be a official GT1 championship sim, would be nice if they include stock version of cars that run in the GT1 champ. I expect better physics, graphics, ai realism...But I'll tell you, If they include some cars from other classes like GT2 and GT3 and a couple of some cool tracks (as Bathurst, Nordschleife, Le-Mans) it would make the game better then "the best racing simulator" (aka Shift 2 XD) but thats maybe way too subjective, we'll see in the end anyway what happens with shift 2 and with what SIMBIN will come up with GTR 3.
Also, I think Simbin should concentrate only on GTR 3 in the future regarding the DLC, bigger DLC is the right way, or a charge free small DLC IMHO. If they want to become eventually better then Gran Turismo, Forza on larger scale and push themselves on a whole new level of respect that they(simbin) surely deserve.