You're missing the point, overthere.
Just because someone is huge and beefy doesn't mean they are automatically a strong fighter.
Put Bruce Lee against someone like Brock Lesnar and Bruce Lee would have a decent chance, so long as he stays out of Brock's grip. It's not about strength but technique.
Also, big biceps don't mean hard punch, you need to KNOW how to punch and a scrawny ass shrimp can punch harder than a bullet. (It's called a Bullet Shrimp and it can punch much harder than Arnie)
Big muscles won't automatically make a Predator go for that person. It's skill, technique and so on. City Hunter didn't look and go "WOW, that guy driving that vehicle looks so beefy!" no, he looked at him use tactical thinking to go past the gang and ambush them and probably thought "DAMN, this guy's smart!"
Glover beat the Predator because he tricked him as you noticed, plus he had a smart disc, hell, YOU could kill a Predator if you tricked it and then sliced its belly with a smart disc... it really ain't that hard with such an insanely sharp tool.
As for Hanzo, well, Predator skin seems surprisingly vulnerable to cutting attacks as opposed to blunt force. Hence why they take explosions literally to the face and shrug it off but a slice makes them bleed. (Kind of how Kevlar body armour is able to stop a bullet but you can easily plunge a knife through as if it were a normal shirt) Hanzo used technique and must have struck an artery or something.
For example, if you slice a human's fermoral artery on the leg, without medical attention, they're going DOWN.
Predators are super strong, but they're realistic and believable. The big charm about this alien is the fact that despite being an intergalactic badass, it has weaknesses.
Think of Predators as big cats. A lion can break a man's neck with a swipe of its paw just like a Predator can most likely do seeing as they shred us to bits... but even we can take on a lion if we act quick and get lucky. And how do we often take on lions? With traps and tools... and how did we defeat all the Predators so far? With tools and traps! I haven't found a scenario where a human punched the ever living green shit out of a Predator with his bare hands yet.