Re: Still some improvements worth having with a new handset for some!
"-3 day battery life (good for relieving me of battery anxiety)"
This may clash with one of your other requests:
"-fits in my child-like hand more easily than the last one but the screen's still big enough"
The only ways, physically, for the screen to be the same size yet fit your hand better are to (1) reduce the bezel and (2) thin the phone out, but (2) means you can't put in the big battery you really need to have a 3-day practical working life.
"-easier to read in sunlight than the last (though still utter pants compared to paper)"
Again, a tradeoff. A display that's good for transmissive light (ie. backlight) is generally bad for reflective light (ie. sunlight). While inroads into this are being made, there have generally been tradeoffs. The closest we've come to is Qualcomm's Mirasol display, as seen (albeit very briefly) in the Toq smartwatch (Where is Mirasol now?), but even that trades off night visibility to an extent.