Well, nobody else said much about StarTropics, so I might as well say something that likely doesn't make sense. Here are a few reasons it might work for diversity or for fans that I thought of.
1. It could be similar to the Kid Icarus revival, in that the developer can do whatever they want because almost no one remembers it. Heck, I remember some people thinking KI would be like Metroid Prime before it was shown, and it obviously ended differently. There's no reason StarTropics would have to just be a different version of Zelda again. I'm not sure what genre they could pick, but I wouldn't have guessed on-rails shooter/3rd person action game for KI either.
2. If they did want to keep it in the same genre, there are plenty of people basically asking for it. I see plenty of people asking for Zelda to change in crazy, opposite ways, and making a different series satisfy some of these people might be a good idea. Steampunk StarTropics, etc. (mostly joking here).
The only real problem I see with it is the sales potential, which I admit is low. Again, I would have though KI would sell poorly. Kid Icarus had the advantage of Smash Bros. style promotion, but Mike Jones could always be in the next Smash Bros., I guess. I'm somewhat unconvinced that it would be worthwhile in that aspect, though.