my opinion: the Swamp can only put up a decent fight against other races in the late stages of the game.
1 at the very beginning their development is much faster than others - in the 1st week you build a wyvern nest and a castle, and already you have an excellent opportunity to explore the map, or gather wyverns for the final battle, thereby gaining a huge advantage over the opponent.
2 the swamp's specialization is defense; playing as an armorer, for example Tazar, as you develop you will suffer fewer and fewer losses.
but there are also downsides
1 on random maps, playing as the swamp, you are positioned in the swamp, which limits your movement and for a week or two you'll have to move very slowly
2 there is no decent shooter.