As someone who has thoroughly enjoyed all the games in the metroid Metroid series, I whole heartedly agree that Nintendo needs another. The Metroid games are really some of the few games on either the Wii or DS that could be considered as appealing to hardcore gamers while making good use of the systems' unique attributes. Incidentally, the craft shown at the and of Prime 3 looks almost identical to a vehicle seen briefly in Metroid:Hunters on the DS in a short cut scene in which one of the other "hunters" (I think it was Sylux) drops out of it immediately preceding a fight with said hunter. A Metroid:Hunters is probably my favourite Metroid game, and a sequel would have immense potential on the Wii; hopefully this is the direction they're taking.
As a side note, I HATE cliff-hanger endings in games. (That means you Halo and either GoW2.)
@wolf FF7 on the PS3 sign me up I'm already salivating just imagining what it would look like. It would also convince some idiots i know who refuse to play it cause it doesn't look good enough.