The A.I times for SuperKart races is beyond a joke. Even starting from the back with maxed out difficulty it takes 1 lap or so before I am leading, and end up racing myself for the rest of race. Is there plans to fix this? I would luv to play multiplayer but I never see SuperKart lobbies.
I have seen them online more times than I expect! At least 2/3rds of the series AI are not-yet properly speed calibrated. That is a tedious/time-consuming task that only makes sense to do when the physics of the vehicles are final or very near final.
In addition to Marc's points above, Superkarts are pushing the limits of what a traditional race car focused physics engine has been designed for. This means that small changes to overall physics in every new build of AMS2 can have dramatic changes to the Superkart AI speed, which again means that it will be correspondingly extra time-consuming if every build should need Superkart AI adjustments prioritized over other AI adjustments (which still are considered work-in-progress anyway) Therefore, I can understand why Reiza would prioritize getting the "average car" AI behavior tuned-in first, and then start tuning Superkart AI once the physics have been relatively set in stone. One exception, though: If Superkarts regularly crash into track objects and thus block the racing line, or if they all get permanently stuck in the sand, that would in my mind be considered a bug and the tracks+corners where this happens should be reported in the bug thread.
Another note on Superkart tuning: For most tracks in my experience, the best setup is to completely remove the rear wing. It also removes the dreadful nose-lift-at-speed and makes the kart feel much more balanced and fun to drive. I'm not sure what plans Reiza has for this, but for fixed-setup races it would be great if the default setup or other parts of the physics can be adjusted to remove some or all of the dreadful understeer at high speed. I suppose some understeer can be OK, but it's a shame if those who don't like fiddling with setups end up disliking the Superkart even if it drives much better when you change the aero balance.
I'm sure it will get some TLC soon, but as you suggest, likely not one of the priority series for updating each month.