It's funny how tradition dominates the use of footwear in sports. Most people would think it is normal to see a gymnast perform barefoot, but not a baseball player. This brings up a good question: if shoes are so important for improving athletic performance, then why don't gymnasts wear shoes? Certainly, gymnastics is one of the most athletic sports, with high-impact landings on the feet. Yet I've never seen a gymnast performing in shoes, or even practicing in them.
Related to this, here is a study(pdf) that looks at the plantar sensitivity of gymnasts and volleyball players. The researchers wanted to test athletes who either regularly participated in a barefoot sport (gymnastics) or a sport that uses shoes (volleyball). The study found that gymnasts had better sensitivity in their feet. Better sensitivity in the feet also correlates with better posture, as I written about recently. Therefore, I would also expect the gymnasts to have better posture than the volleyball players, even though this wasn't part of the study.
Just as you now see top runners doing some barefoot training, I think other top athletes may eventually use some barefoot training for their particular sports.