What is the most interesting observation I have noticed when it comes to game development over the years? Almost everything needs to be reiterated from art, to programming, to design. Consequently, with design, the game has also been reduced and rid of unnecessary bloat. I am still targeting the more casual audience, especially on iOS devices, so the game should be simple and easy to understand.
With that said, I returned from a brief vacation and experienced the game with fresh eyes. And with the help of playtesters, I have decided to make drastic changes to the heroes. At this point, I am satisfied with the fire, cold, physical, and poison elements, but each hero does not have enough utility. Worse, upgrades are independent from one another. Sure you can upgrade an ice mage to slow enemies, but it gets progressively more expensive and he will be doing as little damage as a freshly hired one.
Therefore, each hero's level will be simplified to have predetermined benefits, and most of the heroes will be changed in some way. It will be less about damage, and more about utility.