In general, there are two turning points in a hero's development: level 5 and level 15. When I played a hotseat game with Demons against Orcs, between levels 8 and 15, I didn't want to waste points on unnecessary skills, so I waited until level 15, distributed everything, and finished the game :).
What kind of map is this, small and with only two factions? If so, how did you manage to reach level 15? I played on a small map, and I only reached level 5 and defeated the opponent!