Something that feels premium... If theres one thing the Vita got right was just how premium the handheld felt, specially with that OLED screen (which is sadly removed on the new one). Also an account system that isn't locked to the console as well as dual analog sticks.
As for launch games, I want a killer new IP. Like a good one! And yea, the rest you already mentioned
Oh and More Anime games
PC Specs: CPU: 7800X3D || GPU: Strix 4090 || RAM: 32GB DDR5 6000 || Main SSD: WD 2TB SN850