Yoshio Sakamoto has told Wired that it would be great if Retro Studios would come up with more ideas for the Metroid Prime series.
“With regards to the Prime series, if the team at Retro comes up with an idea that does bring a sequel to the series to fruition, I by all means encourage them to do that,” he said. “But I’m not directly involved with the Prime games.
“In terms of the Metroid series stories that I’ve told, the games that I’ve been involved in, I started with the NES Metroid and took it through Fusion.
“I’m hoping to tie the Super Metroid and Fusion stories together [with Other M], and until I do that I can’t think about what happens after Fusion, but if the concept does come to me I’d like to continue the story and see how far it can go.”
There’s always hope.