Yes, I agree that starting as the Swamp is a bit difficult, but if you get the hang of it, Tazar with Gnolls and Lizards + recruiting troops from the second native faction + recruiting a second non-native hero from the tavern = you can easily take even the most difficult Dungeon on the first day, even without Wyverns (if you get a good start with Gnolls and Lizards). Non-ranged guards are easily defeated, and if there are many ranged units, upgrade the Flies and go for it. The Swamp has the highest speed for secondary heroes on Flies, and if you upgrade them, they all fly at maximum speed. If you scout many Hive factions in the first week, you need to find Sulfur at all costs to get Hydras in the first week, so that from the beginning of the second week, with 2-3 Hydras (Tazar with 2-3 Hydras can take even the most difficult Hive), you can clear the Hives to form the so-called "strike force" of a stack of Wyverns. If you can't get Hydras in the first week, then try to get Cows + Wyverns in the Citadel/Castle. Playing as the Swamp, taking Utopias with Tazar and Cows is a pleasure in the 3rd-4th week, and if you get lucky with Hives and Provisions, you can try it in the 2nd week. Someone above wrote that Wyverns are weak?! And what makes the Skeletons of the Necropolis strong?! That's right, their numbers. In one online game (not mine, though), a Necropolis player and a Swamp player were playing, and by the beginning of the second month, the Necropolis player had just over 1000 Skeletons, while the Swamp player had 140 Wyvern Monarchs. I don't think anyone would call Wyverns weak in that quantity.
My personal opinion, as I wrote at the beginning, is that the priority of factions by strength on a random map at 160% difficulty is as follows:
1 - undoubtedly Necropolis
2 - Conflux, Rampart, Dungeon, and Swamp. The priority of these factions depends entirely on the map layout.