You might as well question the realism of the rules of chess.
The rules of a game dont have to make sense and dont have to be realistic.
They only have to work as a game.
D&D5 is optimized to be easy to handle with nothing but pieces of paper, a pen, and a couple dices.
Thus things are kept simple. Not realistic.
show me how you dodge sword in plate armor :F or hit from crossbow xD
The weight of plate armor is distributed across the body in such a way that it does not significantly hamper mobility, so in real life you would dodge a sword while wearing plate armor pretty much exactly as you would without it.
But that�s besides the point, as the post you are responding to pointed out already.
This isn�t going to change. Your objections are irrelevant here.
