I think that a large prob with animated pit crews would be the positioning and angle of the fuel pump. Each car would have to done individually. While possible, I'm glad I'm not doing it
The people look like 2D cutouts aranged around a 3D car. You know how the crowds look as you drive down the raceway? That's what these guys look like to me. That's not really all that impressive but if you guys like it then good for you.
I was playing Nascar Heat 2002 (XBox) last night System Linked. The cool stuff in that which I hope are in GT4 are networking and pit options like which tires to change, or how much fuel to put in ... such as that. And it also gives a count down for completion. That would be cool, but add in a randomized factor of failure and crew messups for a touch more realism. I can see myself screaming at the TV "DAMNIT GUYS LETS GOOOOO GO GO GO!" as a tire that should be attached to my RX-7 LM rolls across the pit lane ...
I read that polyphony denied there would be changeable weather unfortunatly. As for 2D pit crews, I thought they looked pretty 3D in the video especially in the action on wireframe.
The pit crews are 3D, the weather effects will be limited to a dry track and a wet track, only there will be more tracks that can be driven in the wet than in GT3, the full on variable weather will be in GT5.
yeah perhaps hard & soft trainer compounds for durability/grip in longer races or maybe choosing the brand 
