That's part of the issue concerning these widespread packs. Like take grasslands; most people would probably never consider the armadillo as a contender due to their association as desert animals. And I mean, I don't blame them, I'm used to seeing them in temperate woodlands, so grasslands isn't too far fetched at 1st glance, but there's always another choice that could make or break the pack.
I'm not saying it's bad, and I personally love the fact that the relative vague theme can squeeze in different animals you wouldn't think of normally, but there's always that "this animals could've been better, but what we have is already good"