I liked the handling physics in DiRT 2 enough to overlook its flaws, since the physics is ultimately the core of any racing game. My main gripe though, like everyone else's is that the game was waaaay too Americanized and catered too much to the X Games/Extreme Sports/Ken Block/Travis Pastrana crowd (the stylistic elements, particularly the menu design was pretty cool though). Not saying that they have a bad influence on the game, it's just that it's kinda sad for CM to have to resort to these sort of things in order to sell the game... I actually found the Rallycross and Landrush events rather interesting at first, but there was too much focus on that in the game, and not enough on Rally.
From what I've heard though, CM have listened to the fans, and are putting in A LOT more rally-related content this time round (something like 50 rally cars, not including vehicles for other race modes?), as well as many more environments and tracks to race in. I just hope they don't scrap the Landrush and Raid events completely though, cos they do add something interesting to the game.
And the Official WRC game? Well from what little I've seen, handling physics aren't great, and car choice is extremely limited (only 4 cars in the WRC class - Citroen C4, Ford Focus '08, Ford Focus '09, Subaru Impreza - plus a few more in S-WRC and P-WRC)
Just wish CM had actually delivered on their promise of DLCs for DiRT 2 (how awesome would a Group B/Group A tribute pack have been?), but I suppose I can forgive them if they sacrificed that to push for DiRT 3's development...
Oh, and GTAMADDOG, most stages in CMR2005 (which I think you'd consider a proper rally game) were only 3mins long anyway ;)