I would not be so concerned about weight. If a LR hunter is buying a US Optics scope, it's probably going on a pretty serious rig and people who have setups like that tend to own more than one rifle. Meaning there's no need to build a lightweight scope if it sacrifices anything, as your asking for input on a purpose built LRH scope.
Power range is really personal... while 20-24x on the high end minimum is fine, contrast is absolutely king! Being able to really pick out your target is more important, at least to me. for a true LRH scope, something in the 6-30x range would be absolutely perfect IMO.
Objective and tube diameter... as big as they need to but not bigger... probably 35mm main tube with a 50-56mm objective.
Reticle... i have talked with a few fellow long range hunters, and what we have all pretty much agreed on as the perfect reticle would be a leupold TMR style reticle, FFP, with moa hash marks (assuming moa turrets). something like a 1/8" or 3/16" clear dot in the center. This would mean at lower power ranges it would look just like a traditional scope, but not matter as if your shooting close in low mag, you aren't looking for the ultra precise aiming this allows.
We have found this type of reticle to be great for shooting varmints in the 800yard+ range, as traditional reticles often cover quite a bit of them up! But at the same time, at least with the people i've discussed with this about, have all really liked this reticle for hunting deer and big game as well. It is nice to SEE the exact spot you want to put the bullet rather than covering it up.
Side paralax (sorry Broz, my mistake
), definitely, not much to say here, besides objective focus seems to make a scope cheaper, side focus is much, much easier to adjust without breaking position.
Illumination i would leave as an option, personally i've only ever used it once while LR hunting, which was shooting pigs under a full moon on a whitish dirt road, there it was handy, except it kind of "washed" into the picture, was not crisp like the reticle, and that was with a NF, but if you can design illumination that doesn't do that, it may be useful for some hunters.
One more thing, i saw 2 suggestions mentioned velocity reticles and and drop compensating turrets..... ok, while this may ruffle some people's feathers: i believe these are both gimmicks, for people who don't want to, or simply don't, understand ballistics. There are way to many variables that go into calculating a shot than these turrets offer, at LONG range. Sure, if you want to hit a pie plate 600yards and in, in fairly consistent conditions with a high performance cartridge, sure... but that's not really what i, and a lot of members here consider long range hunting. Same goes for velocity reticles... they are just an even simpler system.
Mil, or preferably moa marked turrets, with an absolute minimum of 80min elevation travel, for a dedicated LRH scope, 100-120 would be AWESOME, zero stop would also be very useful when your going 3-4revs over your zero.
Hope my input was somewhat helpful, very happy to see you and USO take such a personal interest in what we, the consumer, want in a product!