well i have a mod right now, but it's nothing major like The Hell. it's like Varaya & Khan's mod is all. but if what i mentioned is beyond hex editing, then i have no choice but to look elsewhere. do D2 mod editors exist?
Mordor- what does changing the enemy AI do? because i've remembered that goatmen archers are sometimes as annoying as soul burners. so i need to change them, too.
soloing in nightmare and hell can be tough without health leech. many enemies can hit me for 100-150 damage even though i have +220 AC. in fact, it's almost pointless to solo in hell anyway as i would have to go to town every 5-15 minutes depending on how many potions i use.
one more thing- Mordor you said that your mod has 50,000 gold stacks. how did you find the code for it? do you think you could search for that code again? because i did find "88 13 00 00" and i changed it to "E8 FD 00 00" or something like that to get 65,000 gold but all it seemed to do was change the spiked club to a short sword (the one you get for creating a new warrior)
AI determines how long a monster waits between attacks, how often and for how long it delays when walking (walk interrupts), how it behaves, how high or low the chances are to retreat if the target player is too close, etc. etc. AI determines a lot. Everything about it is done by hex-editing. Unfortunately, I can't help you as I'm keeon on Hellfire 1.01 codes, not Diablo. If you find the code chunks tho, there's a decent probability that I'll be of assistance.
Health leech is needed ONLY if the game balance assumes so. In The Hell I made it so that players regenerate life and mana, and regeneration speed depends on high high Vitality and Magic attributes are. This proves to be an excellent passive leech, which doesn't ruin balance, yet solves the problem of having to heal with potions all the time.
Regarding the battle itself, how much you're hurt depends on how you play and stats combined. Armor class determines how often you're hit. DFE determines how well the damage is reduced (or sometimes - increased). It's about balance also. Things like DFE and AC values are pure data and are adjustable simply, a modmaker shoud be smart enough to do that.
I modified gold data in year 2006, back then I didn't even bother documenting my changes. So, there are no clues to it now. I might search for it, but it would show Hellfire 1.01 address anyway. I think it's no use to you.