Additions
For each race, The Frozen Throne adds several new units and buildings, including a player-controlled shop, and one new hero per race. Two new auxiliary races, the Naga and Draenei, have also been added. The Naga feature in all three campaigns, and as playable units, allies, and enemies; while the Draenei, which are actually more sophisticated creeps, are found only in the Blood Elf missions. Both can be put in custom maps if their worker units (the Naga Mur'gul Slave or the Draenei worker) are added via the World Editor. The old siege engines of the Humans, Orcs and Night Elves have been renamed and remodeled, receiving new upgrades in the process. The food limit has been increased from 90 to 100, and the upkeep requirements have been relaxed by 10 food units each, leading to the ability to mobilize somewhat larger and more powerful forces.
The weapon and armor type system has been completely revamped and a lot of units have had their weapon or armor types changed, and the weapon types are effective and ineffective against different armour types compared to Reign of Chaos. Because of this, battles and strategies are slightly different than the ones in The Reign of Chaos.
The expansion and its subsequent patches made the addition of neutral Hero units, which appear in the single player campaigns. Neutral heroes can be used in melee maps via the Tavern, a neutral building used to hire them. The tavern can also instantly revive any fallen hero, with an increased resource cost, and reduced health and mana of the revived hero. A nearby unit is needed to access the tavern.
In addition, The Frozen Throne re-introduces naval battles, which were almost completely absent in Warcraft 3. Although generally only available in the campaign, naval units can be placed using the World Editor and can be purchased from certain buildings in melee maps such as the Goblin Shipyard. To date, there haven't been any half-popular naval battle custom maps.
The Warcraft III Map Editor program now allows the user to do more custom work with regards to editing skills, providing more functions in the triggers, new units, more global map settings, and new tilesets to work with.
Read more about this topic: Warcraft III: The Frozen Throne