This is hardly a new thing, every Iron Man movie (including The Avengers) has introduced a new armour design (see the first official still which subtly charts the different development stages of Iron Man), how else can they justify selling even more merchandise?
The Las Vegas Licensing Expo is always a good place to find sneak peaks of said merchandising, particularly movie posters and other marketing materials, often loaded with hints or clues about the look and feel of an upcoming movie.
At this year's Expo, Coming Soon spotted a new poster for Iron Man 3 striking an imposing figure, all cast in shadow (See right, click to enlarge). Why is it so faintly ambiguous? Probably to conceal the brand new Iron Man design.
This new design is brought to light in the new banner (courtesy of CBM), as seen below, which boasts an increased presence of gold in the traditionally 90% red design.
It's by far the most visually distinct armour of the series but we shall see how it looks in motion.
Source: Latino Review