Larian [Studio]'s given all of these critters a lot of love already, including completely unnecessary and extremely welcome things like animation and poses for sitting on chairs.
If you, like me, want to spend as much time as possible as a badger, there are some limitations. You can climb, jump, loot, open doors and most of the things you'll be able to do normally, but you'll need to turn back to your regular shape if you want to talk to people. In cutscenes and unskippable conversations, you'll temporarily drop your animal disguise, but once it's over you'll shapeshift again. Most of the time, though, you'll have to manually break the spell and waste a charge.
To make up for not being understood by humans, elves and the like, you can chat to absolutely every animal whenever you're shapeshifted. They all seem to know you're not quite what you appear to be, and in some cases you'll just get a line of dialogue telling you to piss off, but some of them will be willing to chat and maybe offer you advice or share a secret. They're all brilliant.