I completely agree with your premise. However, I have to point out that, IIRC, Tasloi and Flind go all the way back to at least 1st Edition AD&D.Probably boring for you to draw, too.
While the 'old guard,' orcs, goblins, hobgoblins, bugbears, kobolds, gnolls & lizardfolk, have pretty much crept into useful niches, every time I see a *new* humanoid race, like tasloi, flind, nycter, witchknives or whatever, I wonder if they are really necessary, or could just be replaced with those already present. Do I need an Urd when I can just have a dragontouched kobold with wings?
Also, I'm pretty certain that Flinds were just an excuse to have Lawful Evil Gnolls. IMHO, alignment is a poor philosophy to design game elements by, as much as I actually happen to like Flinds. (Generally, I liked LE monsters.)