Heroes 5 incorporated a lot from the third game, a little from the fourth, but also introduced many new features, and all the factions were reworked. The developers faced a challenge, but the balance in this game is very well done. Here, it's very important to develop your hero correctly in terms of skills. In the third game, this was also taken into account, but it didn't have such a significant impact on the rest of the game. In the third game, the main skills of the hero were the most important. And many spells in the third Heroes game created a significant imbalance. For example, if someone got teleport, or even better, teleport to a Castle (there is also such a spell in the fifth Heroes game, but in the third, you could also choose which Castle to teleport to), and you didn't have these spells, you were at a disadvantage. In the fifth Heroes game, this doesn't happen - excellent balance.
Well, I don't know!
I agree, in the third game, there was a certain element of luck related to spells, etc., but it was also exciting. And the factions themselves, as I think, were perfectly balanced, and all the advantages equally compensated for all the disadvantages... but in the fifth game, with its variations, like Training, Avengers, and creating artifacts, they went too far!!!
Interesting, beautiful, clever - BUT THEY WENT TOO FAR!!!