I'm gonna assume these aspects from Legacy are the same as in D2R:
No elite items at all.
No exceptional set or unique items. Uniques are still pretty useful, especially for an all nighter.
Monsters are way weaker than their LoD version; Their levels are lower for the most part ( you hit more often with lower attack rating ).
Rare items have less + weaker affixes.
No charms.
Oh, and rare/magic items do not have sockets. The only way to have a socketed rare is to use a SoJ+3 perfect skulls in the cube.
Block chance depends only on the shield and the class (and holy shield) - not on dexterity.
Meele pala builds are rather weak, but the auras help your team a lot. Don't play hammerdin, it's too OP (conc aura works at 100% efficiency with hammers. In LoD it was tuned down to 50%)
Have fun, and enjoy drinking mana pots every 2 sec xD