You can tell just by looking at the art direction, it might as well be teen titans. We have this gay ass comic book clown troupe, wearing outfits from their favourite japanese animes:
When we should be getting something rad, gritty and heavy metal like rogue trader is supposed to be:
If you check the the whole rulebook and not just the cover art, you'll find out that the art direction (& quaility) is all over the place and lots of it is actually shit.
Also the game is not based on the wargame but the fantasy flight RPG series, which has a different art style.
That said, I agree that the art direction could be better, it's somewhat off and doesn't seem to set the right tone. They are probably reusing the artists from Pathfinder games (freelancers?). Though I'll reserve the final judgement until the game releases.
Frankly, the Pathfinder games art and overall graphics were mediocre as well, but the games are relatively low budget and I personally enjoyed both of them a lot.