Q u o t e: does classic have less resists or anything besides no a5 and a smaller stash?
This is the best summary of differences I have so far been able to piece together:
Differences Between Diablo II Classic and Expansion
Expansion User Interface · Doubled personal stash
· Secondary weapon/shield slots, activated by hotkey, called a "weapon switch"
· Mercenary screen
Expansion Mercenaries · Can be equipped with body armor, helm and weapon/shield using the UI page
· Can be resurrected if they die
· Can be healed using potions
· Follow the character between acts
Expansion Character Classes · Druid
· Assassin
Expansion Acts/Quests · Act V, featuring six new quests, one granting free item sockets and another +10% to all resistances
Expansion Items · Throw-able potions
· Charms, including two powerful unique charms that are never dropped by normal means
· Jewels
· Runes
· Sockets greatly expanded, including up to four in body armor, and six in some weapons
· Powerful elite grade items
· Class-specific Amazon bows and javelins
· Class-specific Assassin claws
· Class-specific Barbarian helms
· Class-specific Druid pelts
· Class-specific Necromancer shrunken heads
· Class-specific Paladin Shields
· Class-specific Sorceress orbs
· Ethereal grade items, that cannot be repaired but are more powerful
· Twelve additional exceptional or elite set items
· Dozens of exceptional and elite unique items, as well as rings, amulets, charms and jewels
· Crafted items, made using certain items, gems, runes and jewels in new Horadric Cube recipes
· Runeword items, made using specific rune combinations in specific order.
Blocking chance determined by · the shield, plus modifiers, in Classic.
· a formula using dexterity points, in Expansion.
Resistance penalties are · -20% NM, -50% Hell, in Classic
· -40% NM, -100% Hell, in Expansion
Whirlwind is · unaffected by weapon speed, in Classic
· calculated using weapon speed, in Expansion
Blessed Hammer receives · full damage bonus from auras, in Classic
· reduced damage bonus from auras, in Expansion
Expansion Affixes (or Modifiers, or Mods) all absorbs
all chance to cast
all skill charges
all elemental damage prefixes
all skill tab level prefixes
all socket adders
all quantity adders for throwing weapons
all attack rating/damage mods vs. Demons and Undead