Tactics for the Swamp (Fortress).

but there are also downsides
1. On random maps, when playing as the Swamp faction, you are located in a swamp, which reduces your turn and you will have to move very little for a week or two.

1. A hero with only Swamp faction units does not receive a movement penalty when moving through swamps.

Added 20 minutes later
About the Lizardmen:

move to the first level (without enhancement, but that's still silly, I agree)...
but you can also not move it, but just enhance it... because it's a very weak ranged unit for level 2.

1. The Warrior Lizardman has the highest defense of all level 2 units, and its attack is on par with archers and Magogs. Damage 2-5, only better than the archer: 2x(2-3) and the Raider: 2x(3-4), and also the Storm Elemental: 2-8 damage.
2. 15 hit points for a level 2 ranged monster is not bad. The archer, for example, has 10 hit points.
3. This is far from the most useless level 2 unit. Gnomes and zombies are more useless. In addition, the Magog is weaker than the Warrior Lizardman. And the Fireball of the Magogs usually still only hits one enemy.