i dont get armor class mechanic, why more ac give more dodge ?
how characters with 8 dex and heavy armor can dodge so much ?
heavy armors should reduce damage not give more dodges, heavy armor mastery feat give less damage from psysicals attacks not more dodge
robes and dex should give more dodges while heavy and con or str or both damage redution
robes also less magic damage vs user and stats like int more magic defs etc and magic more vs plate users like plate
med armor hybrid of them
heavy plate and shield that give more dodges is complitly nonsense you dont dodge with shield, you block with shield
So the premise is not so much the attack misses as it fails to penetrate and do any harm. Instead of having two full mechanics for dodge and protect DnD chose a simpler solution of combining them to a single mechanic.
You are correct for a more "realistic" solution there should be a chance to hit, that would be modified by DEX and a skill with weapon or shield to parry. Then once a hit is made armor would negate some level of certain damage types based on the armor. Heavier armor would negate the dodge ability making it easier to hit but less likely to do damage.
However as noted, this system was developed to table top, pen and paper with dice game play. The current system is an evolution from the old system, THANK GOD because THAC0 sucked.