It would be cool if there were more sea creatures like the octopus villagers. Maybe like turtles or something. I also think there should be more reptiles of some sort. I hope the animal crossing team can create some new species. I hope they dont add anymore bird type creatures though. The birds of any kind are my least favorite species in animal crossing.
Omg I forgot we even had a Sloth in the game at all.... Face palm. Though having an actual villager one would be pretty cool. ^^ I have a feeling they'll never do bugs or fish because of being able to catch them. However they do have Octopi villagers so there is hope! I'd love a butterfly Villager XD
I kinda want to see Bat, Seal and Grasshopper villagers. They're interesting but weird creatures, but they'd still make a nice addition to the species of the game.
Also, Grasshoppers villagers could work, even though you can catch those insects of the same name. Look at the Frogs or Octopuses; they also have counterparts you could catch, display, and/or give to the museum. So why not Grasshoppers?
I want cranky, jock, and peppy sheep so I can make an all sheep town and still have all the different personality types without having to use other species to fill in the gaps.