An important goal could be to increase rationality in the world. I believe that would do more good in the long term than trying to solve aging. The best way to achieve that through this suggestion box would be an idea that is simple and direct and hard to get wrong.

For the first two points (simple and direct) better education would help. How about improving science classes by including actual science, that is, learning to change your mind and to look at evidence. However, I fear this will be very hard to get right, and hard to get accepted by teachers. Does anyone have other suggestions for improving rationality?