float_your_boat.esp
An animated rowboat that appears to float and bob was in the vanilla files, but Bethesda never used it until making Dawnguard. All the rowboats that are in the water and don't have other statics inside them have been replaced with the animated version.
thalmor_disguise.esp
AI packages related to the quest Diplomatic Immunity had the wrong conditions set. Altmer players can now disguise themselves using hooded or unhooded Thalmor robes or elven armor, which seemed to be the original intent. Other races still must have hooded robes.
spell_loot.esp
Adept and Expert level spellbooks can now be found in boss loot. Warlock-themed loot has the highest chance.
damage_skill.esp
Weapon damage bonuses shifted from 50% skill and 100% perks to 100% skill and 50% perks so its less punishing to crosstrain.
http://skyrim.nexusmods.com/mods/29213