Game saving that came in two parts.
1. Replacing passwords with saves.
2. Replacing those original cartridges with the old save batteries with a saving system that actually works! As in, one that doesn’t delete your saves if you turn off the system’s power. I think Gameboy was probably the first console that had working saves, some NES games were better than others.
My least favourite one is when companies try to make their controllers more “comfortable” by rounding them in a certain way. For whatever reason, controllers like the Dreamcast and Gamecube one always cause my hands to cramp up when playing games with any degree of action. Games like Skies of Arcadia on Dreamcast and Animal a crossing on the cube were fine, but Soul Caliber and Mario Kart were murder on my hands. Which leads me to my next QOL I liked:
I love split controllers like the Wiiremote and chuck, as well as the joy cons, and any VR controllers I’ve used.
Another one is making all games available digitally. A lot of people love the physical copies, I’ve never been a fan. While digital distribution hasn’t been perfect, for me its always been vastly superior. Especially on Switch where you can basically import without having to pay ridiculous extra fees (my imported copy of FF4 is in the region of 300 USD with inflation). Each generation, from Wii (which had VC and Wiiware), to 3DS (which added most games), to Switch (which unified the divided libraries), has shown vast improvements. The big flaw of the earlier consoles is they didn’t carry over. If the Switch EShop has fixed that and 100% of the EShop content will be on Switch 2, then that would be massive (interface fixes aside… the Switch EShop is built for massive lists, but it seems the hardware limitations struggle to handle it—as it’ll occasionally crash once you’ve scrolled down past 100 games or so… also, videos occasionally skip, videos should never skip).