Aaron Bitman wrote:
I know that it makes no sense. The system was designed to be FUN, not realistic.
Imagine a system where your AC improves but your hp remains the same. One lucky hit (like a natural 20) from a goblin could fell your 20th-level character.
More hp with each level doesn't make sense, but I think that it's supposed to simulate a certain kind of fantasy story. I've read several of REH's Conan stories with a line like "Conan had taken enough wounds to fell five normal men, but he kept on fighting."
End quote
I imagine the system to run something like 'the lucky hit stabs your fighter in the chest, causing a nasty bleeding wound. You stagger stunned for a moment then recover and swipe the goblin back.'
The lucky hit causes a wound which stuns and maybe causes a penalty until healed. The high level fighter can keep going because he is tougher than the low level goblin.
Improving AC by BAB means that a high level fighter does not have to rely on magic items to improve his AC. He gets better because he is better at it. He can still benefit from being tougher (i.e. hp) and fight on as you have said with Conan. Adding this rule in does not detract from the tough hero theme and does not make it less fun.
As an aside, I have ran several campaigns using harnmaster, which uses a realistic damage system whereby the characters take individual wounds which build up until either the character gets stabbed in the heart or drops from multiple wounds/bleeding. This system was lethal but still fun to play. Unfortunately, the game company concentrated on producing world supplements rather than adventures (which is why I like Pathfinder) so I came over to D&D again (via exalted). I still find the same old combat mechanic which existed in the 1980s when I started playing. This is why I hate it. I hated it then and I hate it now!