I don't know why but I didn't think of SNSD or EXO as big groups. All the members are essential and add something, there's no filler with either of them.
A lie. I can easily shave EXO down to 5 members (6 if we're talking them as 12).
Yea, as a Red Velvet fan I had trouble telling them apart when I first got into kpop. Now it's super easy. Sometimes I look back at photos where I got them confused and now I can easily tell who is who.