Why is Tokka more popular than Sukka?

Answer 1

Probably because Sokka and Suki clicked at the begining of the series and they couldn't just end the Kyoshi Warriors there, they had to come back at some part. So, Suki joins the group. They were already together, so it would only make sense. But I wish they more Tokka too :(

Answer 2

Probably because in the show Sokka and Toph are shown together more than Sokka and Suki and Toph is liked by more fans than Suki. Also, many people tend to want what they can't have.