I guess WotC D&D-team is more focused into update the crunch. The creation of new IP is for Magic team.
Other point is if they are going to create a new PC specie, or only the same racial traits but with a different look.
The Magic wiki says there are: badgers, bats, frogs, mice, lizards, otters, rabbits, racoons and squirels.
And they are sentient animals, not humanoids with animal traits. This means they keep their original size. Do you remember any tiny PC specie in 5ed? And the size difference with monsters like ordinary predators (wolves, for example). A simple fox would be a serious menace.
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The lore says if a humanoid travels to Bloomburrow automatically changes to an animal shape. This also should be a size change.
Maybe we could see some "Ral Zarek's Guide of Inhabitants and Creatures from Bloomburrow", but more focused to PC species and a short list of monsters.