So? Even in real life you probably wouldnt try to land on your feet if you jump off that high, because you will die anyways. I believe ragdoll are kinda changed in GTA V, or its a bit dumbed down due to hardware limitation.
You can´t read, can you? I´m talking about heights like 3 meters, where it´s impossible to land without tumbling and hurting yourself, not about deathly falls from choppers or buildings.
In GTA4 if you jump from 3 meters, Niko jumps down vertically and TRIES to land as well as possible before eventually not making it and landing not too well hurting himself.
In GTA5 if you jump from 3 meters, your character falls as if he was not conscious from the moment you start falling. He doesn´t even try to land as well as possible, he just plummets ragdolling totally inert.
And may I remind you, that´s a poor excuse, as hardware limitations were exactly the same: blu-ray and PS3. Mind you, actually GTA5 has 5 more years of know-how with these limitations so it should be better if anything.