...And then I went to DFO.

It's obvious. DFO players are simply a different demographic; people here care more about looks than sheer power, and they see playing a puny loli mage for power as demeaning. In other words people tend to play classes closer to how they see themselves as, only branching out when bored or they are curious about other classes. Because of that, you're less likely to see mages (or Eles in this case) because few people want to play a little girl. That's kind of why you see tons of Slayers and Gunners, not because they are strong but because they are cool.

As for me when it comes to avatars, I am a mix of looks and stats. I tend to pick what looks nice, but will only buy it if it has the stat I need.