I know everyone wants the Captain Falcon GTA F-Zero, but the whole reason the franchise appeals to me is its purity as a racing game. GX pushed the absolute limits of what arcade racing could be, and there hasn't really been a non-realistic racing game since that has a skill ceiling that high. It's absolutely mind-boggling what Amusement Vision created with GX twenty years ago.
Adding vehicle weapons, RPG mechanics, or a GTA like open world would probably garner more sales and interest from average joe gamers, but doing so would lose sight of what makes this franchise great. All that is probably more likely to happen than not should there be a new installment, as much as I hate to admit.
I'd say vehicle weapons is right out and is the line where it ceases to be F-Zero, but I don't see how RPG mechanics or open-world preclude including racing challenges with an extreme skill ceiling. I mean, with the current Soulslike fashion trend I'd say they could market based on that, particularly with Armored Core 6 demonstrating how "RPG elements with a very low stat ceiling" works well with skill-based gaming.