Honestly I think I'd rather the next race(s) be half-race(s). I mean...
...we already have one in the main story of Heavensward, XIV's own 'Lilisette' if you will...
...so there's no reason not to have them now, the precedent is set. As for why we don't have more bestial races... well, it very much is a cultural issue. You see it all over Japanese media through out the centuries. Half man, half beast characters depicted as little more than humans with animal ears with maybe a tail, fur used mostly as a censor to pass them off as 'nude'. This is in stark contrast to what Western people consider as half man, half beast. We refer to characters such as these as furries and has only really caught on in Japan in the last couple decades. Yes, I am aware of the Darkstalkers character that's a werewolf, but how many of those can you remember outside of that game?