Humans will always show up in some way (even if they're not named as such). There are many reasons why they're in almost everything, but the biggest is that they're us - it provides us with a prime, solid connection between reality and fantasy.
Elves traditionally contain the highlights of what humanity wants - beauty, brains, athleticism. Admittedly, though, a game can do without them if they're creative enough with the other races. It's kinda the route I'm taking in my story - I started with the idea of elves, then abolished them and added something that gives a vague resemblance to them.
And as for the other races - just be creative in what's presented and it'll work fine.
Cat-people included.