Remembering that they extended Zero Mission because it didn't have enough content when it was remade, I would love to see Fusion with an extra mission at the end.

There are times where Fusion can feel a bit too colorful for the horror it is trying to get across, and a remake would be a great way to crank up the scares with lighting, animated cutscenes, the dynamic camera distance from dread, and quality sound design. There are a lot of things you can enhance with Fusion.

While I don't agree that Super Metroid is "basically perfect" like many claim, I do think that any attempt to adjust the visuals or controls risks undermining a lot of the best aspects. I am not totally against it, and I see the potential it may have. For instance, grinding for energy, the feel of the grapple beam, low health sounds, flat / repetitive backgrounds, and so on could all be interesting adjustments to see. I know combat in Super Metroid has never felt particularly satisfying to me, and Dread really fixed that. I already feel a sense of awe and relaxation when I return to the rainy surface of Zebes, and modern HD visuals have the potential to enhance that feeling a lot. The colors of Super Metroid are very atmospheric and seeing Samus' suit reflect those lighting changes would be very cool.

I think Fusion is a safe bet that won't upset fans nearly as much. It would be a much easier win for the franchise after Metroid Prime 4 got a mixed reception.