Other M was outright bad, not just mediocre. Terrible controls, ugly art design, FUBARed structure, all worse problems than the story. Iansane's right, game reviews are terribly inflated for the most part (e.g. AC III reception), and what examples are there of a mediocrely reviewed game climbing the ranks of opinion rather than vice versa? (Based on gameplay, not cult factors like with Deadly Premonition).
I think Metroid Prime has had it's time, and while a full HD iteration would be pleasing, I don't see where it could make a big enough gameplay splash. At this point my vote would be for a retail 2.5D game for the WiiU with bonkers sprite work and animation. Pick up from Fusion, actually incorporate Metroid DNA powers, go fucking nuts with the map, 3-4 times the size of Super Metroid. You could even do a Fez or Lone Survivor type thing where the map is arranged three dimensionally and the navigation is 2D.