This game will be awesome, but only if it improves on the first game substantially. Things that need improving (in my opinion):
- More interconnected maps. All of the other Metroid games had maps that were very full and compact that were constantly connecting with each other, having all sorts of shortcuts and secret passages. Metroid Prime had a little of this, but the maps were so sparse - the game had long sections where there were few or no choices on which way to go. Also, it seems very apparent when you look at the 3D map.
- Warp points. This is something that was annoying in Super Metroid, but even more annoying in Metroid Prime. It's hard to blame Retro for staying by Metroid's roots, but I got tired of the backtracking, especially to certain places like Phendrana Drifts or whatever it was called, where you had to go through ___ first. Metroid Fusion didn't have this problem because of its map setup where everything connected to a central point, but that would seem artificial outside of the context of a space station. This kind of formulaic map hurt Majora's Mask IMO, so I'd much prefer the warp point solution. After seeing how well it works in games like Castlevania and Zelda, I would definitely expect this improvement.
- Customized map labels. It's not a huge thing, but I would like to be able to mark on my map when I see a missile pack that I can't pick up yet. It would eliminate the trouble I always have trying to backtrack to a place that I still haven't opened because I can't remember what the obstacle standing in my way is.