If I was the designer (which I'm not,) I would have Heroes join Armies instead of existing out on their own...
So for instance, instead of having a Hero exist as an independent unit, a Hero joins a unit, and his stats and the armies stats combine.
Why you might ask? Here are my three reasons.
1. Eliminates the Hero vs Army conundrum.
Currently, I have to choose between having a Hero centered army and a squad centered army.... now they work together, where I can design heroes to complement squads rather then attempt to choose between one or the other.
2. Adds depth to the game
Currently, Heroes and armies have very similar functions...kill things quickly. What is the difference between the classes if three of them have the same function! If we implemented this function, Heroes could now be a specialty so we could have
Assassin: Target's enemy Champions in 1vs1
Defender: Makes the unit stronger + Gives the Unit cc
General: Gives Army wide bonuses, at the expense of being frail + Improved Economy
Mage: Casts spells, but does not improve the fighting ability of the unit
Warrior: Makes the Unit stronger + gives the Unit offensive/killy abilities.
3. Makes far more sense
Instead of having Heroes run by themselves in the middle of battle, Heroes can now move with a unit and "feel" like an elite super soldier among an army instead of THE army itself.
Of course, whatever you guys do, I'm sure that you'll find the best path going forward.