I think it is worth noting that at this late stages that sort of change will not be possible. When this sort of idea was last brought up I think the main problem was having to make a new art design, model, animation set, ai for each creature limits this.
All the maps are split between the 4 biomes and each biome has some unique creatures in it. I think it has also been teased that some game modes have something in it called a 'phantom' that was spotted in the loading screen hits but so far we know nothing about them other than this.
So would I love to see more unique wildlife per map but I am also aware that the resources for doing that would probably be better spent on adding more monsters and hunters.