No, vote kick is a bad idea because people will use it to kick gatherers. Go with an FC or premade group of people where you all have the same idea of what you want to do. Some people go in to gather, and gathering is a part of Diadem. Those people you say stay in the air the whole time are probably looking for gathering nodes. I went with FC and took ages to find some gathering nodes. I spent more time flying than gathering because map is so huge. Sometimes I would end up flying by close enough to party so that the it allowed me to loot roll, which was not intentional on my part. Sometimes we just ended up close enough to each other.