Most of my playtime has been Veela. They are viable. Small speed differences like Kallard vs. Khurite may not mean much but Veela speed difference is noticeable even on flat ground. It's not GREAT before you start using your other clades to help it, but it's noticeable.
And it's precisely because they are viable I don't think they need too much more of a movespeed buff. Kallards are viable, Thursars are viable, Veela are viable, Ohgmir are viable, I don't think that will continue to be the case if the speed gap grows a ton.
Buff dex in other ways, give Khurites higher attribute total, consider racial bonuses as opposed to just clade bonuses. I feel like a massive speedbuff to fast races moves us further from true race balance. Not closer toward it.