three things:
1. a power source (battery?) that charges itself by RF signals which reach everywhere.
2. a form factor resembling a paper clip or safety pin and weighs about the same.
3. a cost approaching “give-away” status for anything under 500LM.
My dystopian point of view...
So, what will flashlights of the future look like?
Man … that’s dark !
He’ll, if aluminum becomes more expensive than copper, perhaps they will all ship in copper.
Emisar!
I’d like to see the shake light make a comeback with newer technology. 
More flashlight powered by body heat would be interesting if the planet is going to keep getting warmer anyways.
For anything in the future, they must have those Space Age rings around them, like
Nothing screams FUTURE!! like those Space Age rings.
3 Space Needles and a Nazzi Magnetic pulsar ring?
What is that?
I see now, World’s Fair leftover stuff.
Cool for it’s day though.
At least it’s high-CRI.
Humans will evolve faster than the torch. Soon we will be able to see in complete darkness.
We’ll all be “snobs” or “CRI grown ups” 
Batteries will be getting smaller and more energy dense, so I see a shift towards smaller form factors. Reflectors will gradually be phased out for optics of various kinds, and LEDs will get more efficient with better cd/mm² so you won’t need a big xhp70.2 to efficiently make 5000 lumens and throw far. Drivers are also improving. I think we will see more buck/boost drivers soon.
Hate to break it to you, but the Brain Disintegrater is already a reality
And it looks like this
In the future we will all have “Surgical shine job” that let us see in the dark…
Exactly
Can’t be any good, ’cause it ain’t got any Space Age rings.
People of the future will not be able to see anything clearly farther than 70cm. So, all they need is a smartphone camera light. :-D
’Cept we won’t because all cigarettes will be banned including Menthol Kools, so finding any will be extremely rare.
Thinking back to my youth in the early 1980s, my first flashlights were these from radio hack:
Lights have come a LONG ways since those days. I owned the 2AA incan shown on the right in the second pic, it was my first EDC… LOL. Radio hack would practically give these away as a way to increase battery sales. I was also a member of the battery club. You get a card every year and each month bring it into the store and they give you a free alkaline battery and punch a hole in your card. There was 2 stores in my area so I got double free batteries!! FWIW the store employees were real A-holes too BTW… they hated serving anyone who did not help them make commission. You couldn’t even browse the store without that annoying door buzzer triggering them to run out to harass you. Especially as a kid. I’m amazed they remained in business as long as they did.
I don’t see significant changes or advancements until LED efficiency improves. Basically incremental enhancements as Lumens per watt and thermal heat/BTU per watt improve.
I took my 2 week old Sofirn IF25A and 10+ year old 6P + Malkoff M60. Both lights are cold tint, so they both favor Lumen output over CRI & tint. The M60 is copper foil taped so it fits very tight tight with the 6P host for thermal conduction.
I ramped the Sofirn down to about ~210 Lumens to match the M60 on a bathroom ceiling bounce. Ran them for 15~20 minutes. Both lights got warm to the touch, and both matched each other in output as they warmed up. So if there is any thermal dimming it was equal to my eyes. The Sofrin did get warm to the touch, but not as warm as the 6P. It was maybe ~half as warm feeling… slight but noticeable. Neither light was hot to the touch.
Biggest difference was the color tint and current draw. The 6P/M60 draw was .87A while the Sofirn drew only .2A after 20 minutes of constant-ON warming. The SST20 LEDs at low output have an awful green tint. I am not a tint-snob at all so for me to notice… it has to be really bad.