As a parent I will say I didn't name my child after an Avatar character, but there are some really nice names to consider.
Yue, Suki, Korra, Katara, Kya, Suyin, Asmai and Jinora are all beautiful names that wouldn't be thought of as bad. Depending on where you are from or travel it is possible to meet several people with these days.
As for the boys, Tenzin and Rohan are popular names in India and Tibet. I also like the names Jet and Bumi, but probably for middle names.
Most of the names used in both shows are names used in different parts of the world. So I guess it really depends on where you live and your culture. But I do agree that you should try to pick a name where you child isn't ridiculed or teased.