I totally agree with you on this. My top vote would be to use technology to figure out how to protect humanity from unrestricted technological advancement. For example, 'The Grey Goo' as one candidate. Synthetic Biological Attack is another. Nano-fiber poisoning is another. AI-Gone-Rogue is another. These are the kinds of threats that the future holds in store. Our brightest minds should be diligently at work figuring out what technologies are feasible to protect humanity from them, or if there is no theoretical defense, at least warning us of that fact. Loudly. Better, though, to produce the defenses, because nothing is going to stop their development, and all of the resulting unintended consequences. A good starting point for what the threats are is Bill Joy's article "Why the Future Doesn't Need Us".