Haha now you've done it. Get ready for a big one
If I was thrown onto the project and given full creative control, here's a few considerations.
In my head, an optimal Mario Kart ride is:
#1. Accessible to as many people as possible, meaning limited / optional AR and an easy motion profile. Super Mario and Mario Kart are widely known for being easy to jump in and play, whether you're incredibly young or a senior that's never played a game before. No height requirement would be ideal.
#2. Primarily based around spectacle as opposed to thrill or gamification. The former cannot be accomplished given #1, and the latter inherently limits your demographic appeal unless you commit to an immediately understandable game system like a Blaster / Shooting Gallery attraction. A ride does not give you enough time for a non-gamer to get the hang of a complex game like this. Save that kind of design for the self-selecting Power-Up Band Challenges next door.
If someone self-selects to want to compete for points and throw Shells at opponent racers using the AR goggles, there can be extra gameplay to accommodate that, and rewards for Power-Up Band players accordingly, but it should only add to an already great non-AR attraction, not take away from the experience for those who opt out.
Even if AR is utilized however, I actually think a slower ride would help with the stuttery nature of the existing AR functionality, which generally works best with static scenes rather than moving ones, meaning a slower ride could hopefully mean less cluttered jittering from the effects across the screen.
Mario is an IP born from games, so making your theme park ride a game isn't special, it's the norm. And no doubt, any actual game is going to be far, far more enjoyable than anything you can cook up for your 4 minute attraction. Making a game that grandma can understand in 4 minutes with no prep time, and that a college kid can master on their 82nd run is incredibly difficult, and more than likely just ends up in both being disappointed for opposite reasons.
#3. Working off of #2, that spectacle should be practical as much as possible. No show scenes, important transitions, or major characters should be exclusive to the AR functionality. If someone who gets motion sick easy wants to ride Mario Kart without the goggles, they should be able to do that without missing important show moments like the Rainbow Road reveal or Boom Boom on the airship.
As this ride couldn't be fast or physically thrilling to remain accessible, you would need to engage guests in some other way. Ideally, practical sets and figures would more than make up that difference.
Mario is an IP born from the screen, so making your theme park ride screen-based isn't special, it's the norm. It can be used for supplemental theming, or for effects that truly would not work without the use of screen-tech, but whenever you can get away with a motion figure or other practical effect, you should.
If you're given those few directives, a slow-moving ride primarily based around practical spectacle within the world of Super Mario / Mario Kart, there is
so so much you can do.
Stuff like the practical Chain Chomp and Piranha Plants are the barest minimum. Why is the crowd of onlookers AR-exclusive? They couldn't build a few simple motion Koopas and Toads to fill those seats? Why are nearly all of the characters and bosses screen-based? As I said before, the land captures the look of these games perfectly within physical sets and motion figures. Just bring that energy inside here.
- Mario and Luigi animatronic / motion figures drifting their karts adjacent to us for a short moment, before drifting into a warp pipe themselves.
- Practical flying Boos, Magikoopas, Paratroopas bobbing up and down in certain scenes.
- A scene where the airship is shooting real Bullet Bills that look to be flying over past us.
- A Toad figure in a kart spinning out after hitting a Banana peel.
- A big physical Ty-Foo figure that appears to blow at you, sending you spinning a bit, while a fan blasts you with a big gust of air.
- Smaller and more numerous limited motion figures like Bob-Ombs and Mecha-Koopas like we see being produced in Bowser's Castle in the queue.
- Ending with a big Lava Bowser figure as the boss fight, into an equivalent non-AR Rainbow Road transition would be one of the coolest things across the entire resort imo.
These, among any other number of small and big practical effects to fill out the space. Make this thing look as dense as MiB: Alien Attack, mixed with the dynamic scenes of Forbidden Journey. Like a Small World-style Fantasyland dark ride in the world of Super Mario / Kart.
Mario Kart is just the easiest functional way to justify a ride vehicle and narrative beats within the world of Super Mario. We already aren't "racing" against the other Kart of guests, so just take it as a set of narrative beats for pacing purposes and work from there.
A Super Mario ride should take the constantly moving and energetic nature of Super Mario Land and highly concentrate it, and the same for a Mario Kart ride. These are both essentially the same series. Boom Boom and Pom Pom, Ty-Foos, and Fuzzies* aren't in Mario Kart 8, but they
are in the SML Mario Kart ride. They are already not sticking to Mario Kart perfectly here, so just use the Mario Kart "big race" idea as a justification to go crazy with spectacle, rather than as a mandated checklist of gameplay beats to attempt to replicate.
*technically they were added in very late DLC for the switch port but you know what im saying