No, Geralt doesn't die from 1.5 meter fall considering the ratio of in game height to real life. I tested that.
I learned how to avoid damage by tapping or holding the jump button in time and Geralt do a roll thing. It is pretty realistic. I like the fall damage.
Have you ever watched basketball games? Even a 1 foot drop would snap your leg. I have seen that.
The good thing is that I learned how to use ladders which made the game more realistic. Unlike other RPGs where you can jump from ledges and dismiss the ladders which makes me think why do game developers make these ladders when I can jump like shit.
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If I could look down over the edge of ledges and cliffs to see where I was going... If I could drop and hang before letting go (like the NPC's do)... then the amount of damage Geralt takes from falls would be within acceptable levels. But I CAN'T do those things. I can't see where I'm going. Excepting ladders there is no way to drop down and hang from the edge of a ledge before letting go and thus mitigate the height. As a result fall damage feels kinda cheap.
Just sayin'.
if you tried jumping from ledge to ledge, Geralt can actually hold on to the other if you hold the jump button. You can try it while falling to a cliff. The game is not automated so you have to press buttons if you fall or jump to hold on to something or roll over.