The engine is not really the issue. They could develop the Frosbite Engine to handle proper Dirt racing physics.

I think the main show stopper here is that EA doesn't make niche game. They make games that will sell millions of units. So I highly doubt that they will develop a accurate Dirt racing game, they will do what they did with every franchise: Make the gameplay incredibly "accessible" but dumbing it down a lot. You will end up with another generic racing game with a slightly more slippery physics.