I think we're well overdue for a Metroid V. The DS has been out for four years now and still nothing about a new 2D Metroid in the original series. IS has busted out new Advance Wars and Fire Emblem games since then but no Metroid.
Ian, IS isn't responsible for the Metroid games. The Metroid series was always done by Nintendo R&D1 who are now called Nintendo SPD1. This is the same division that made all the old Wario Land titles as well. The problem with this studio is it's very small and can only handle one project at a time. After Metroid: Zero Mission came out, they've been working on the Wario Ware games, and have now moved on to their new series, Rhythm Tengoku.
This is why the latest Wario Land on the Wii was done by Good Feel instead of SPD1, because SPD1 was busy with Rhythm Tengoku DS. Of course considering how good a job Good Feel did with Wario, I wouldn't mind it if Nintendo allowed them to make a 2d Metroid as well. I mean, the Wario Land games in a way are similar to the Metroid games, and since the Good Feel has shown they can deliver a great Wario Land title, it would be that much of a stretch to think they could also deliver a great Metroid title.
Plus since Metroid Fusion and Zero Mission were both made made on the Wario Land 4 engine, so why not make a 2d Metroid on the Wii using the Wario Land Shake engine?
But who does Metroid have?
Yoshio Sakamoto is still very much alive. People need to realize, he the true creator of the series. Gunpei Yokoi was only the producer who over looked the projects because he was in charge of Nintendo R&D1 at the time, but the man who actually directed and did the majority of the work was Yoshio Sakamoto. Not to mention, Super Metroid which is considered the best, was ALL Sakamoto. Yokoi had barely any involvement in Super Metroid's creation since he was busy designing the Virtual Boy at the time. Which left Sakamoto to be in charge of pretty much the entire game with Makoto Kanoh helping out.
Oh, and Yoshio Sakamoto played a big role in Metroid Prime 1's development by overlooking things and giving major input as well. Metroid Prime 2 and 3 on the other hand, he played a very minor role in their development. Which might explain why Prime 1 is the most like the 2d Metroids while Prime 2 and 3 started to differ more.