I'd like immortality, only so far as "aging doesn't kill you". Just so we're still able to assassinate all the future Hitlers of our species.
A method of straight up sending knowledge digitally. As in, being able to know a thing just by looking it up and downloading the appropriate file or whatever. Humanity would probably stop being so shit.
Never underestimate the ability of humanity to continue being terrible!
Things I wish existed:A combination element creator (take particles, make periodic table) and generalized 3D printer. This would be really useful for space voyages. You could do this to create more rocket fuel, for instance, or execute a mission to build an artificial planet around a nearby star without carrying all the materials from the start.
A piece of headgear that circumvents your eyes and sends vision from cameras in place over your eyes directly to your visual cortex. Now pair this with a pair of full-spectrum cameras
. Or, to be a bit more tame, you could replace FLIRs with this and an IR flashlight. Also: see UV light without the relatively complicated process of removing your eye lenses. (There would likely be special "blink" functionality if it turns out the human brain doesn't like it when blinking doesn't appear to be working anymore.)
A visit from the TARDIS fairy.
I'm sure more will come to my mind after I've posted
.