There's a spinning coaster at Worlds of Fun, for anyone interested in checking one like that out.
I would love to see the Balloon Ride show up in the Grand Expo.
As for Flooded Mine, I don't think 3D tech is necessary, but some sort of tech could help increase kids' interest. I mean, take out the dips and Pirates of the Caribbean is basically like the Flooded Mine, minus the shooting. However, it's HUGE compared to FM; the WDW version is somewhat like 7min long and the DL version is close to 15, if I remember correctly.
I will always maintain that SDC needs a "People Mover" in the vein of Haunted Mansion. Something that is constantly moving, eating 100s of people an hour, and is long enough that the wait in line is worth it.
More interactivity in the queues could help, too. Disney's been doing a brilliant job adding interesting things to see and do while waiting in line, and while SDC rides rarely have the kind of waits Disney rides do (though I don't know how Kids Fest is, since I haven't been there for it in ages), it could still help keep people's attention. Especially for rides like Powderkeg and Fire in the Hole, which take a long time to queue because of the small number of people who fit a single train.