I still dont like it. The one from the first two movies was the bestetstestest.

I agree with you for the first two movies having the best Batmobile.

Afterwards, he toned down the unnecessary things (like the freaky off-road wheels, etc), built up the bat motif, and jazzed up the functions he would use. So the car there is supposed to be a "rough sketch" for the multipurpose vehicle he eventually ends up with. Remember, this is a pre-Year One movie. His car in Year One looked very rough.

Also keep in mind that Batman has roughly a dozen different tricked out cars stashed in and around Gotham. he doesn't have any one Batmobile. He has a variety of vehicles (including a heavily modified military Humvee) to suit a variety of needs. And, of course, in the apocryphal Dark Knight Returns, he has a frickin' Bat-Tank that he refers to as the "Batmobile".