Both games, even if they are too short, did a fine job in worldbuilding, so I think it is logical for this next game to have Riddick step out of contained areas and explore the galaxy with reasonable freedom. If the third installment is yet another short 'prison-breakout' game, then I think Starbreeze and Diesel will fail yet again to attract more people to the Riddick universe.
If the sequel has Riddick exploring a complete world (Elder Scrolls - will never happen-) or at least a world that is divided in over a dozen larger levels (like Deus Ex and DE: Human Revolution), then the franchise will get a well deserved popularity boost.
What makes the world interesting is its savagery. You can see it more prominently in its Nanomech+ devices. It is like the universe is in a dark age, but with the aid of high-tech and alien technology. Even though what I've seen I wouldn't recommend for the Nebula or other important SF prizes, it still has potential to be something big and make strong statements at the same time.
Time will tell what will happen. Its been 4 years since Assault on Dark Athena, so hopefully they are making something memorable.