And pretty much any non-metallic color (even ugly ones!) looks good on a Bronco!
It's as tough a decision as you'll likely ever have to make. Not the "do I change it" decision, but the "what color do I change it to" decision.
I see no reason to keep an original color on a Bronco unless you like it. It has almost zero to do with future value, and if you're not selling it then screw future value for now. With the "not selling any time soon scenario", then by the time you do sell it the rig is probably going to need new paint again anyway. And then you, or the new owner can decide whether it should go back to original or not.
Yes, collector car values depend a lot on originality. But Broncos are not there yet in spite of their increasing values to collectors. These are not '67 L88 Corvettes with "Pomona 1968 Championships" decals on the side with race fuel stains marring the original black paint. They're still just poor little 'ol utility vehicle orphans from Ford.
;D
Original paint? Yes, a little. Original color? Not so much.
New paint sells Broncos no matter what color they are. Original in fantastic shape will open eyes and wallets, original paint with patina less so, unless it's a collectible in other ways too.
New paint sells no matter what color unless it's just a fugly color on a Bronco. If it looks good and even remotely Bronco-like, it does nothing but enhance the value. And as a restomod in primer it sounds like you're way beyond the original paint stage.
Doesn't sound as much like you're wanting to sell it soon as you are just not sure about painting any older vehicle anything but it's original color?
I would paint it like you want.
Now unfortunately, you "only" have to decide what you want...%)
Paul