There are a lot of video games and books with REALLY cool animals that the main character may ride, or other characters may use. Some examples may include the Jamgut from Kya: Dark Lineage (video game), or the Loftwing from Skyward sword (video game), maybe even the polar bear in East (book). A lot of you may even have similar ideas, and want to share them. :) so share your ideas and maybe they will come to life in the game. :D
John Ravenblossom here with some bad news. Sadly, Kingsisle is a business. Which means they'd need the rights to use things from other games. I think it's a great idea but, very illogical...Sorry!
Now let's get to the less bad part. I'd love to see (Most likely won't happen but) a Tron Light Cycle.