Board Thread:Speculation House/@comment-14138255-20140815002519/@comment-25308133-20140825190032

Agreed. Ren's focus seems to have been on straight aura control. While you probably do need good aura control to be a dust mage, that's not all there is to it, and he likely lacks that additional training. Also, Ren's aura control seems to be above and beyond the point dust mages need (since we've never seen Weiss use aura like Ren does and she's a pretty good dust mage).