Take the basic idea of Assault (with modern controls), and give it the content of 64 and you've got a solid game right the hell there.
I think what I would want from Star Fox (I'd also be fine with just "another 64" if it was actually good for once but I feel like people are well sick of that road by now) is like this, but taking a very specific approach to it.
First, make it feel good to play. My strongest memory of Assault, aside from finishing it in a day and the on-foot sections being crushingly boring, was how you could crash the Arwing right into something and there was practically no feedback, it felt like nothing. And fully implement alternate paths like in 64 so the game isn't crazy short. Do something where you can't reach the "real" ending without visiting every level to trick people into thinking it isn't over after the first playthrough if you want, but I don't think the idea that this style of game simply won't
work today is extremely well-founded either when there hasn't really been a notable one since Star Fox 64 itself. Unless we want to entertain the idea that Star Successor ever had a chance even if it was 20 hours long. I'm not going to buy that people don't want traditional Star Fox anymore until one that's actually
good flops.
But the big hook here is going to be expanding the game with alternate gameplay styles, and we really need to completely reexamine how we're doing this because they keep trying to do it and they have historically always sucked. The ones in 64 were okay, despite basically being slightly worse variations on the base gameplay, and I think that's because they served an effective narrative function. There was something conceptually compelling about diving to the depths of Aquas or following the Macbeth supply train in the Landmaster to try and take it out.
So I think there are two goals to keep in mind here. The first is to not stray too far from the arcade appeal of Star Fox while also creating meaningful variation from the base on-rails gameplay. The all-range mode dogfights are probably the best example of this. They're literally the same gameplay aside from the turning and the addition of that one maneuver I can never remember the inputs for, but they provide the opportunity to do different scenarios you couldn't pull off in an on-rails level. Star Fox Zero, conversely, I would say is a good example of what not to do. The Gyrocopter is just completely divorced from any idea of fun, never mind something that makes any sense in the context of the rest of the game. Star Fox has done stealth, it was literally the level that inspired this one! There had to be a better way to expand upon that than
this. Then there's the chicken walker mode. This has the same problem as a lot of Zero's additions in that it just feels fundamentally pointless. You can transform at any time, but being on the ground offers zero advantages. The sections specifically using it have you go inside of a ship or something to step on buttons and shoot targets and do some light platforming, and it's all so... game-y and bland and uncompelling. Not to mention silly.
Which kind of segues nicely into the other objective: to use these alternate gameplay styles to take advantage of Star Fox's space opera setting to create really cool and interesting scenarios. One of my favorite childhood games was Sly 3, and this was essentially what it was all about. The whole concept of the game was to make a sort of playable heist movie, and it uses its large cast of characters and different gameplay styles in service of executing whatever crazy scenarios it wants. Sly always sort of played like this, with way too much time devoted to random things that weren't platforming, but 3 went all-in on character writing and the individual mission scenarios saw a huge boost in quality from 2 (If you want a quick idea of what I'm talking about, compare the first proper missions of
2 and
3). I'd love to see Star Fox do something similar, but faster paced.
It should probably stick to being a shooting game no matter what happens, I think it's pretty much never a great idea to do
complete genre shifts from level to level because it's not what you came for and it often suffers compared to the "main attraction", but this is a direction I think the series could really shine in and capture a whole new audience with even if it doesn't change anything about how it fundamentally plays.
Here's how an example level could go. Like a lot of Star Fox levels, this one is inspired by a sci-fi film, in this case the opening of Revenge of the Sith. You begin in a standard on-rails section, with the goal of reaching the enemy flagship during a space battle. All sorts of potential for different events or dialogue along the way, depending on the context, but you eventually reach the flagship and just barely manage to make it into the docking bay. Now, you have to continue on-foot, because there isn't room for the Arwing in here. There are a few different ways to do this, like maybe it could work like an on-rails light gun arcade game, or maybe like a relatively modern flavor of third person shooter. Whatever the case, I think the defining feature of these sections should be Fox's relative vulnerability outside of a vehicle, with you needing to rely on cover or well-timed use of the reflector to survive enemy fire which you no longer have the shielding to absorb or the space and maneuverability to avoid. You've still got the same fundamental aim and shoot arcade scoring stuff going on, but now with a much more vulnerable character to give a different sort of thrill.
And you could keep it simple and go with the classic "destroy the generator and escape before the thing blows up" scenario to cap it off. Or maybe they've captured General Pepper, and you're here to rescue him, and all sorts of things start going wrong after you manage to reach him, with the rest of the team getting involved to try and cover your escape. More intricate scenarios would also give so much more opportunity for the rest of the team to actually do things besides flying past you and asking for help. Like, Slippy could try and hack doors and elevators to help you escape, and you could do scenarios like having to hold enemies off while he gets the door open, or being sent to a bunch of different floors where different things pop out at you while he tries to get an elevator under control. Maybe Falco goes in with you and splits up to try and draw attention away from you, and then you have to meet back up during the escape and cover each other. And we haven't even considered all the things you could do with the concept of alternate mission endings and outcomes leading to alternate paths!
Hell, they could even let you switch perspectives and play as other characters from time to time if they can swing it. The issue with this was always that they were functionally interchangeable, so there was no reason for it, but you might find places where it can work from time to time if you allow them to take on totally different roles in a mission beyond just piloting an Arwing.
Anyway, if you embrace this direction, the possibilities for interesting Star Fox levels are practically limitless, you can imagine as many different vehicles and planets as you want, any sort of objective, it's such a natural direction to take it in and I think if we actually got to see it executed on it would appear downright criminal that we've been doing nothing but watered down 64 stages for so long.