The first campaign will involve the Humans. Rob said that he, like many of us, like the duality of reign and rain. Three will be upgradeable up to three times, and one will be nonupgradeable. Bob responded that spells will be permanently upgraded, and not player-controlled as far as what Level you cast. In other words, if your Archmage has Level 3 of Blizzard and you are low on mana, you cannot choose to cast only a Level 1 version of the spell.
Mines are now exhaustible.
Non-exhaustible mines are deemed bad for game balance, plus they discouraged expansion and map exploration. The advantage is that there will be no huge banks of servers, as there are for Diablo II's realms, but there will be some means to prevent cheating. The food cap is set at 75. The cost for a unit will be 1 food, except some units will cost 2. Heroes will cost 5 food.