Batsuit: At first I thought the best approach was to make the costume out of a kevlar mesh with ceramic plating. The end result would look something like the "Arkham Origins" costume-
If this came to be I wouldn't complain. It's a good look. I however think it's little bulky, and doesn't lend itself well to stealth or flexibility.
Since Bruce would have been at this a while he would have had a bit of time refine his costume. I would be a nice easter egg to see some of these bulkier and older costume on display in the Batcave.
My next thought was what would an appropriate material be to create the Batsuit. I settled on the real world innovation of "Shear thickening liquid", essentially it is a gel that absorbs kinetic impact. When the liquid is disturbed the particle's collide causing resistance. So I think the costume should be based on that concept with a light kevlar coating on top. The whole thing would be interlaced with circuitry allowing for regulation of body temperature and the ability to give Batman a wake up call if he is knocked out.
I think a dark grey version of the fabric used for Captain America's Avengers suit would work well to achieve my desired look.
I would use a fairly similar look to the "Dark Knight" cowl that incorporates the lower part of Captain America's Avengers mask. Specifically the bit that goes around the neck. The cowl would be separated from the cape and the rest of the suit (can't believe it took costume designers as long as it did to give him the ability to turn his head) much like it is in the Dark Knight/Dark Knight Rises.
The cowl would have lenses on it to cover the eyes. These lenses would allow thermal/infrared scans and would also allow sonar vision, like Daredevils', not with quite as much range as the "Dark Knight". There would be a radio/police scanner built in to the ear piece which would also allow the ability to hear from longer distances or through walls with a touch microphone built in to his gloves/gauntlets, much like in "Batman Beyond".
The gloves/gauntlets wouldn't really look that different to the ones used in the Arkham games. They would have shuriken launchers built in able to hold three/five circular bat shuriken with a variety of different ones to insert. They would also be able to discharge electricity in order to stun opponents. A few other tools would be kept in them e.g lock picks, blow gun and darts, laser cutter and bugging devices.
The boots would be bulkier than the rest of the ensemble but would have soles designed to reduce noise and grip well. The toe cap's would be reinforced. A few tools would also be kept in them.
The cape would be much like the one Nightowl uses in Watchmen material wise, but in black. It would be bullet proof and tear resistant. It would also have glide functionality much like Bale's cape.
Now on to the utility belt. Design should be the same as "Dark Knight Trilogy" but with bigger pockets.
Utilities-
UV ray proof smoke bombs, explosive capsules, incendiary capsules, cryo capsules, batarangs, grapple gun, bolas, lock pick kit, forensic kit, hacking device and a laser cutter.
I also think a sonic device would be a good way for Batman to do some damage to Superman pre-kryptonite discovery. Give him a sensory overload, kind of like in "Man of Steel" when he first starts to develop powers.
I found this when googling images. Pretty much perfectly epitomizes the look I was getting at.
Sound your thoughts in the comments!