In your opinion, which faction is the strongest in Heroes 5? Let's discuss the advantages and disadvantages of each faction.

I agree, but in buildings, peasants simply join, so you can send one hero to gather peasants, who can then be turned into archers.

Just like any joined unit, and level 1 units are all bought for free in dwellings, although there aren't many of them, maybe two dozen. It's faster to run around the map and recruit them. Necropolis is still better in many parameters, which makes them the strongest faction in Heroes 5, all other things being equal.