As to the refit design being used, well there isn't really enough shown to judeg that is there?
The bridge section of the pre-refit Enterprise didn't change that much between the series and the film, though it did change quite a bit during the series. The deeper, more refined, hull panels are probably more of an aesthetic choice because they can make it more detailed that way. Back when the original series aired the model making technology wasn't as good, or affordable, as today so a perfectly smooth hull would have been easier to create then. At one point they were even using an AMT Enterprise model kit to film other ships like the Defiant. The place where it will really show, if they recycled the refit design, is in the main deflector dish and warp nacelles. So far the teaser really only shows the saucer section and the updated lettering for the ship's name.