I am SUPER excited for the new UD3 to release, which is why it kills me to be the one who gives a negative opinion of the new poster.
At first I was just excited to see something new, but once the initial excitement passed I wasn't that impressed with that I am assuming is the official poster for the film. Looking at this I know nothing about the movie other than Boyka is back and it screams "straight to video."
First off, I am not sure what message about the movie I am supposed to take away after looking at this poster. To the casual fan, I would think most everyone would think that Boyka is fighting Chambers again and they just re-cast Michael Jai White's character.
Second, the photos aren't that great. This is a movie that has one of the strongest cast of martial arts fighters ever assembled and the poster does nothing to sell the audience on that point. All we really see is that Boyka is back and he is still ripped.
Thirdly, what is in the background exactly? Is it a prison, a warehouse, do they fight in the street?
And lastly, which is more of a personal preference, the colors don't pop enough. Adkins and Jenkins blend right in with the background.
Here is what I would love to try as an alternate version of this poster. Get a profile picture of Bokya on the left side of the poster from the shoulder up facing right. Then get a profile picture of Dolor on right right side of the poster facing left. This would create the two main competitors facing off with each other, which alone should tell the audience that these two men will compete against eachother. The background would be a stock photo of prison bars. These two facing off would occupy the top half of the poster.
Below the picture of their faces is a smaller photo of what is one of closing shots of the trailer where Dolor is throwing a low kick and Boyka is countering with a superman punch. A still shot of that would give the poster a great action shot and once again reiterate that this is a martial arts movie that takes place in a ring.

I would also photoshop in above the action shot all the flags from the competing fighters countries as if they are hanging from the ceiling. (which they are in the film). This will help sell the international tournament style of this movie.
To give the poster a little more international martial arts feel and show how this film is different from the previous two films, I would try to give all the remaining competitiors a thumbnail size picture of their face at the bottom and list the country they are from below them. Or maybe use their counrties flag as the background and just list their names under the photo. Guys like Lateef Crowder and IIram Choi are not well known in the US, but do have a cult following and are very well known internationally which should only help sell this movie to more fans.
Lastly, I would give the movie a great tag line which I don't have on the top of my head. I am not suggesting to use this, but something like "The worlds greatest prison fighter has just met his match." Something like this would sell the audience that these new fights, especially Dolor, are badass.
I would love to take a stab at this concept if I could get my hands on some hi-res photos of the images I mentioned. I would also just need to know the specific countries the fighters represent in this movie so I know what flags I would need.