This is something I've kind of wanted to see for a while. I love new Races in general, but for me, a lot of the fun is learning about these new *cultures*. The Hrothgar and Viera have both been very cool, but have without a doubt had a bit of a rocky start.
So, I'd submit that an equally-cool, but more-efficient idea might be to simply introduce new "Clans", which are essentially the same character-models we already have, but minor aesthetic differences.
For example, perhaps a Hrothgar clan whose heads are more "Canine" than "Feline"? And, were it possible, maybe they could be a little less top-heavy (although that might be too extreme for simply change Clan).
With us going to the Moon, it might be a great time to give some love to the "Keepers of the Moon" Miqo'te, but perhaps there could also be a small sect of those who worship "the Eclipse", who have some marked differences as well?
As well, maybe further distinguishing these new Clans, you could alter their Standing animations slightly, to give more personality?
For example, the Au Ra; I've always hated the fact that the Xaela males have the same prim-and-proper, uptight standing animation as the Raen. To me, the Xaela are a much more rough-and-tumble culture, and their standing animations should be more at-ease. Or maybe a "third clan" would be more reptilian and hunched-over, a little more evil-looking?
Just a thought, obviously! But I do think it could be a cool way of expanding on different races, and maybe even setting-up future content (ie. a Midlander clan based on the Walaqee, Radz-at-Hand, or even a long-overdue Far Eastern clan; or for Roegadyn, maybe a Clan based from an area we've never even HEARD of yet).
What are you guys' thoughts? Any particular "Clans" you have in mind? Or even aesthetic differences you could see being cool for each race? For myself, I wouldn't mind an Au Ra that maybe has bat-like ears instead of horns, so we can actually see earrings!