If I could make any change I wanted, I would make it illegal and/or impossible to display advertisement to someone without prior consent. No spam, no pop-ups, pop-unders, malware, clickbaiting, punched gorillas, max-volume ads, interstitinal ads, all that bullshit gone. The world would be a better place.
If it has to be a technological change, I would wish for a universal connector. Everything going in and out of my computers, screens, drives, etc. is zeroes and ones anyways, why do I need twenty different form factors for those bits? I want one cable instead of power, audio, HDMI, DVI, VGA, USB, mini-USB, micro-USB, lightning, thunderbolt, ethernet, and all its relatives.
Also, it should be a bus. One cable into computer, into a hub, and from there into screen, external drive, lan and whatever else. Power across all those cables to all the devices.
A man can dream, yes?