Although I know that (unless something HUGE happened in the industry) Nintendo will never fork over the Metroid license to Crytek...
The prospect makes me tingly inside.
The best thing that could happen for the Metroid franchise is simply for Nintendo to beef-up Retro and hand the franchise back to them. It was the most popular it has ever been in the 3D gens in their hands and its doubtful that anyone else would be able to engage the current fanbase to a higher degree. First I'd rather Retro handle another IP perhaps a full blown Donkey Kong not merely a retro side scroller, but no doubt no one would better revive the Metroid franchise than Retro. Crytek themselves are a poor choice for Metroid anyway. Metroid is so much more than merely a third or first person shooter. Crytek's specialties don't really apply to the creation of a game like Metroid.