We have dismounters, but to be honest, the only person that regularly runs around dismounting is Harry Potted. The rest of us are on chars that don't really do that. You have to admit though, when 3F shows up to a fight, you can expect to be bola'd like no other, over and over, until all your mounts are dead. I don't ever start out with any bolas, but at every fight I end up with at least 5 in my pack that I've picked up from Maria, Gonzo, Judah, Deftech, Emilia, Etc....
As long as the game makes a huge difference between being mounted and dismounted, that's going to happen. Also, a dismounted evasion mage (i.e most of the Japanese players in 3F...) can be killed a lot easier when he can't run off screen as fast.
*shrug*
Edit: Stratics doesn't like Japanese text input... bah, I CALL DISCRIMINATION!