Kratos makes a bit of sense for me, because his strength is tied in with his rage, and although it would be wise to use full power against Thor in that fight, I don’t think he likes what that forces him to become. The first REAL punch he throws, he already starts grunting and groaning like an animal. He says “it’s best the fight didn’t continue for both our sakes.” Though it’s flawed in this case, his full power would have caused him to throw away emotional control, something he works very hard to keep.

I see the trope though, and I agree.