@NImH "Zero was actually really fun if you didn't expect a game which actually catered to you as a fan of the franchise as it has already existed."

Zero was buried beneath some pretty stupid gimmicks, and it not only didn't launch well, it isn't going to age well. It wasn't giving the franchise a fair shot, appealed to virtually no one, and sold poorly. The lesson Nintendo is going to take away from this is: "Well, I guess they don't really want a Star Fox game after all," and not "Oh, maybe we should make sure the game we are making it was that demographic wants before we try to sell it to them."

But the other problem is the way that the "Krystal Trilogy" shattered the Star Fox fan base, because there are now effectively two different groups. You've got your Classic Star Fox fans who only want space flighty shooty games like 64, and you've got your Krystal Trilogy fans who would gladly follow the franchise almost anywhere it goes as long as the game is of passable quality and furthers the 64-Adventures-Assault-Command story line, which means including all of the characters established within that continuity--because that's the real reason these fans keep coming back.

Zero didn't deliver on either of those fronts. It failed to appeal to either Star Fox community, and any fans it may have garnered are going to become a third disparate branch clamoring for something the other two don't want.

It's Sonic Syndrome.

Unfortunately for Nintendo, there isn't a way to satisfy the entirety of both of the major fanbases at once. Anything you do to try to incorporate ground mechanics in Star Fox is going to displease the Classic Star Fox community, but admittedly exploration and ground missions are an essential part of 50% of the Story Star Fox Community, and a good chunk of that community prefers the ground missions. Adventures might have just been Zelda in Space, but people loved that. Assault might not have the best rap, but the people who enjoyed the ground missions really enjoyed the ground missions and loved the multiplayer. So if Nintendo makes a shooty-space classic Star Fox game with the new Star Fox characters, the story fans will come to it, but they won't be entirely satisfied. Meanwhile if you try to incorporate Adventure/Assault mechanics, the Classic Fans won't be happy about it.

Usually I suggest releasing two distinct series: Continue "Star Fox Adventures" as its own series with Assault-quality space battles during some portions of the game and a greater emphasis on exploring contemporary Lylat System areas, and a classic Star Fox series which doesn't necessarily continue the story established in the Krystal Trilogy. In fact, you could take it all the way back to the SNES continuity, include Fay and Miyu, and make it "Star Fox 3" in a parallel world. The Classic Fox fans get what they want, and the story fans don't have to buy two games to keep up with the established canon which they enjoy.

The problem as far as Nintendo is concerned is that making games to suit a story is an affront to their development philosophy, as is making an "improved" version of the same game without adding "something special" over it.

So that's where we're at. Nintendo has established a franchise which thrives on its story and its very specific gameplay with disparate core audiences who want to follow each of those specific elements, who don't usually overlap, and who only want more refined iterations of the gameplay love, but Nintendo as a published doesn't handle storied properties and doesn't release refined iterations as it goes against their creative mindset. It's a sad state of affairs for the franchise.

F-Zero is in almost the exact same predicament, by the way, although its fanbase isn't split the way Star Fox is. That said, I think Nintendo kind of wonders what the point is, since it's "Just a Racing Game" and they have Mario Kart. I think WaveRace might be in that boat as well.