Part of the "how long is your leader length' equation that's rarely mention is trolling speed. How fast are you trolling with just a 16" leader? Don't answer in mph, just in wire angle....45 degrees? 50-55?
If you are running 16-18 inches leader, but only 25-35 angle on your wire, then you are appropriately matching your leader length to your fishing speed.

I troll pretty fast, and think a 24-30 inch leader gives a hoochie or ace-hi enough action while not making it too difficult for a fish to grab.
I've had 16-20 inch leaders on, but for the speed I run my boat it looked way too wild. Each angler needs to find their own happy-medium based on how they fish.