A few points why:
All weapons would do massive damage if you land a good blow and most battles would last from a few seconds to maybe a few minutes if you have the gear most would be able to wear: light armor or clothing. Most would not be able to use heavy armor efficiently without some basic training.
Spells would kill you much faster comparred to the game-play.
None of us would be able to use magic, thought this can easily be avoided.
Proper heavy/plate armor(some light armor are plated and would give simialr effects) would change the course of 90% of the battles since swords and axes have little effect IRL and maces/hammers will only do major damage against legs, arms and head and even then you need hard hit to make a difference since plate armor is designed to counter this.
Archers would quite easily kill anyone without plated armor, at least the archers in Skyrim since they all appear to be well-fed, well-trained and more similar to the English Longbowman than the common archers present in our history.

