So after playing Dirt 3 for a while, and then playing Dirt 2 again a bit, I have to say unfortunately overall Dirt 2 is a better game.
The driving model on Dirt 2 is more fun. I’m not sure what’s more realistic, but Dirt 3 handles much tighter and twitcher. It punishes drifting and powersliding a lot more. Whereas Dirt 2 really feels like you’re sliding around a loose surface, and you have to use that to your advantage by shifting your weight around and drifting and sliding and planning out your turns. There’s more things that go into driving in Dirt 2, you have to manage your center of gravity and weight shifting, throttle application during turns matters more during turns, cars respond in a more varied way to partial braking and throttle, generally planning your line through the course is trickier, etc.
Aside from weather, there’s more variety in the tracks of Dirt 2. More types of environments, and more different types of courses - Utah and Baja Sprint are two entirely different sorts of courses and Dirt 3 doesn’t really have the equivelant. Dirt 2 courses are also wider and less boxed in - you could recover from going offroad a bit whereas in Dirt 3 the paths are a lot more walled in to prevent you from cutting as much.
Dirt 2 looks better, although I may be alone in thinking this. Everything is sharper and more detailed and vibrant.
Dirt 3 lacks a few essentials that Dirt 2 has - any car on any track hugely increases the variety and longevity of the game by giving you way more different ways to play, and it has raid tracks which are my favorite kind of race.
Dirt 3 does have some nice stuff. Cat and Mouse is the big one, it’s a lot of fun. Transporter and Outbreak are alright. It has way more cars over more eras, which is cool. It has weather and night which is aesthetically very cool but they only went half way with it. It seems like they were afraid to make the game actually difficult, so they reduced the effect that weather has. The background at night is so bright that you never really struggle to see anything, the rain never really coats your camera or windshield and makes it hard for you to see, and the snow isn’t all that different from driving on gravel - although for all I know that may be realistic when you drive with spiked tires.
I’ll keep playing Dirt 3 because it has unique stuff about it, but I think I’m going to go back to playing Dirt 2 occasionally too.