There seems a variation in the quality of the CGI used in the 2 trailers seen. I can’t proclaim to be an expert on VFX, but more knowledgeable people online have speculated that the trailer has been produced with digital effects in various stages of production. We’ll see in January I guess.

As MoTA shares a number of the big production staff as Band of Brothers and The Pacific, I very much doubt they won’t be as gritty and realistic as possible.