The balance in Heroes with the Lord of the Horde has improved significantly. Now, each race has a choice of warriors and diverse tactics! In general, the balance in Heroes 5 can only be compared to the balance in Heroes 3! It's excellent in both! Who wants to argue?
1. The fifth installment has a good balance. (I agree, it's definitely the best in the series.)
2. The fifth installment has the same balance as the third. (The third installment has no balance; it's the most unbalanced part of the Heroes series. That's why they cut Necromancer and Castle in tournaments.)
On the Former Friends map, on the Warrior difficulty level (the most balanced), on days 7-8, I consistently capture the gold, sulfur, crystal, and gem mines (sometimes I manage to capture the mercury mine).
2. In the mid/long game, if the Academician gets Armageddon, it's a brutal hit-and-run with new golems.
I haven't played enough with the other races to draw far-reaching conclusions.