Golden Fish Sticks were ridiculously valuable compared to their effect. I might as well sell the 6-stack of them and buy 20 potions. At the moment, you can heal yourself faster with potions; use potion, 150 healed, 5 seconds later, use potion, 150 healed. 300 healed in 5 seconds during combat, in oppose to 300 healed in 10 seconds outside of combat, yet Golden Fish Sticks are supposed to be some sort of useful quest reward. I suggest increasing their heal to 500.
At level 6, I still have 9 intelligence, making it impossible to cast the spells which cost more mana than I even have. I understand that warlords aren't spellcasters, but if your spells gain mana cost per level, then the hero needs to at least gain some small amount of mana as well. I suggest 0.5 intelligence per level (1 intelligence per 2 levels) just so that his mana will at least raise over time.
Mana cost of abilities increases far too much per level, making leveling the abilities a bad idea for Warlords. Level 1 Heart Strike costs something like 24 mana, and deals 50 + 50% ability power damage and lowers target armor by 2. That means, on a level 3 hero, 72 damage and lowers target armor by 2. Heart Strike Level 2 deals 100 + 50% ability power (122 damage) and lowers the target armor by 4, while costing 48 mana to cast. So the mana cost has doubled, while the actual damage has gone up by about 75%. I suggest increasing the mana cost of abilities as they level by somewhere between 20% and 50% of the base mana cost, otherwise there is no point in leveling them as mana efficiency is important.
Morbrough Grunt's Pauldrons supposedly increased armor by 2, health by 25, and spirit by 2. They did increase the spirit, but I did not gain armor. I fiddled around with my items and noticed that its armor bonus did not stack with Morbrough Grunt's Cuirass's bonus of 2 armor. The health didn't stack between the armor and pauldrons, either.
Heart Strike level 3's mana cost went up to 95. This is absolutely ridiculous. Level 1 Heart Strike on a level 5 warlord, including the bonus ability power from stats, deals 78 damage and lowers the target's armor by 2, at a mana cost of 24. Level 3 Heart Strike on a level 5 warlord, including ability power from stats, deals 178 damage and lowers the targets armor by 8, at a mana cost of 95. That's 4 times the mana cost with only a bit over twice the damage. You seriously need to work on balancing mana cost increments; have a constant increase of about 50% of the base mana cost; not a previous value factor. Otherwise I might as well just keep it at level 1.
Escorting the Engineer Zazgaz was far too easy. He had incredibly high health, and very high health regeneration. Purely for testing purposes, I held position, did not enter combat, and let him fight his way back to the base. He reached the base with full health. What's the point of a quest that does itself? Please, make him weaker, so that this can be more interesting. I suggest lowering his health to 600, and lowering his health regeneration to 2/sec. 1350 health, and about 10 hp/sec, or something like that, is way too fast for a beginner area; I don't even have to protect him because he's even stronger than I am.
Strength of Earthsong lasts for 10 seconds. That's not long enough to be at all useful for such a high mana cost. Since you already increase the armor and health regeneration per level, the duration might as well remain constant. I suggest raising the duration to somewhere between 12 and 20 seconds. Believe me, it might not sound like much, but 12 seconds would make it much more useful than 10.
Rage of Earthsong is not mana-efficient at all. Consider the mana cost, and 10 damage bonus for 5 seconds. That's basically simply dealing 40 damage over time, as he will hit about 4 times in a second. Meanwhile, Heart Strike deals significantly more damage, with the affect of ability power. I suggest increasing the damage of Rage of Earthsong to 8 seconds, to make it more worth spending mana and skill points on.
Health potion heals 150 instantly, costs 15, usable in combat. Tasty saucage heals 300 over 10 seconds, only usable outside of combat, costs 45. Why would anybody buy sausages, when it heals less per gold, and takes time to do it? You should lower the price of sausages to 20 gold, so the player can have the option of faster heals, and usable in combat, for higher gold price, or sausages which can only be used outside of combat but cost less for the amount of healing.
You also need to increase the cooldown of potions. With such a low cooldown, they can be spammed to the point where if a player is terrible, he can simply grind gold and then spam potions. It looked like their cooldown was 3-5 seconds. It should be somewhere between 8 and 20 seconds for proper balance. I know from 5 seconds to 8 seconds might not sound like much, but trust me, that makes a difference.