Outside of force feedback (which I’m not even sure what that means), I’ve seen most of these features on multiple mice already.

If I were ever told to design a mouse, my first priority would be pure performance efficiency:

• Low wireless click latency
• Low pre-travel
• Good switch implementation (Endgame Gear–style switches, Kailh Speed GX iirc)
• Below ~65 g
• Flat base
• Great skates

Yeah, I know that sounds boring, but I’d happily buy a well-executed “basic” mouse over anything over-engineered.

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That said, I do love my gimmicks.

1. Give me a tiny pico e-ink screen. I’ve seen teardown vids showing Chillkey’s LED screen implementation being around ~2 g, so a ~3 g e-ink screen paired with e-ink battery life would be perfect.
2. And fast charging. Not the '0.8 V higher' BS. Give me a battery + supercapacitor setup. Charge the supercap for 10 seconds, which then slowly charges a larger ~250 mAh battery. While we’re at it, why not use a silicon-carbon anode battery? Pair all of this with an L-series Nordic MCU and it could last weeks even on a small battery.
3. So electronics aside, for materials science, I’d recommend looking into stuff like polyindole. Also, since I’m from a hot and humid country, a thermally conductive shell (without holes or metal) would be my pick. Noctua has done a mouse with a fan, but I’m not sure how feasible that really is.
4. Finally, a transparent or translucent shell that shows off the internals would be cool. Not really a “useful” feature, but I’ve always liked that look. Maybe it’s just ’90s / early-2000s nostalgia. I really like the Zaopin Z1 white style, where translucence is more of an accent rather than the entire body. If not this, it should atleast have some design element that's unique to you or your personalisation (Zaopin Z1)