I've actually been taking stuff off my personal bows, and shooting for a more "low tech" setup.
Assuming, of course, that you have good arrows the most impactful products I've noticed are release aids and sights. If someone has reasonably good hand-eye coordination and the physical strength to draw the bow, I can have him/her shooting well accurately enough to hunt in a couple of hours, with these products. That's the easy part. though.
Most of the "advances" I see today, seem to be aimed at taking the archer out of the equation. You've got a problem with fletching/arrow clearance don't bother tuning and trying to figure out and correct the problem, just get a fall away rest. You've got a problem with noise/vibration, don't worry about it, just hang another pound, or so, of vibration damping products on it. And so on.
You see some of the evidence in a few of the questions on this, and other, forums. "Can somebody give me the answer, or tell me what magic product to buy, to solve my problem?" Which, loosely translated, means "I want the answers but, I don't want waste my time at the target butt trying to figure them out."
Kind of like my grandkids. They drive all over the place and can text without missing a beat (and they blow me away on the computer). If, however they have a flat or their car won't start, or if, GOD forbid, the car has a standard transmission they are stranded.
I guess what I'm really trying to say is that more isn't always better and the most impactful thing you can add to your bow, in my opinion, would be wear and tear due to long hours of practice and enjoyment