How many factions are there?

In my opinion, the ratio of 9 races: 3 good + 3 evil + 3 neutral is the most optimal.
Because this ratio is present in Heroes of Might and Magic III (which is why it is my favorite).
It is true that with a large number of races, it is difficult to maintain balance and diversity.

P.S. In my opinion, the 5th part embodies all the best from the 3rd part + successful innovations (primarily regarding skills), and the battle itself has been simplified (in the form of hints about who goes next and the number of killed units - in the 3rd part, you had to count everything yourself).