I imagine the incentives here are to remove failure modes and weight, so perhaps the more-streamlined appearance is the result of a more-complex build that has fewer parts and weighs less.
Does that image look like a render to anyone else? Not doubting it’s real, just confused- esp. if you compare it to the photos of raptor 1 and 2 linked in another comment. Maybe it’s the background scene that makes it look too perfect?
They've moved all the fiddly bits inside of the less fiddly bits which will mean they don't need all the engine shielding (mass) to protect the fiddly bits. Yay.
Comparison between Raptor 1, 2 and 3: https://preview.redd.it/iq1xjc5h1dgd1.jpeg?width=1024&auto=w...