Im not sure if the swamps are going to be updated since mountains won the biome vote at Minecon. But i had an idea just in case they do decide to update them in the future. I seen frogs were a new addition, also I was thinking Alligators. Sounds dangerous and they could be, but in the same vein as polar bears. If you took one down though they could drop Alligator skin. That could be crafted into an armor type suit. Stronger than leather and gold but under iron. Also im not sure if they have swamp villages yet or plan too but that would be cool too. Just a thought.
Im down for them adding all animals to be honest lol, However, i think i heard somewhere that the developers of minecraft are starting to dislike us killing animals. Idk how much of that is true but, if it is then we might not be able to get alligator armor.
Idk why, i think they wish to promote not killing animals in real life. Though if that were the case, i think it would be better to teach people not harm animals, and remind them that this is just a game... then to keep the animals from us.