Because silk robe is limiting by classes, have half of the original defense as the flower wing and each refine gives the usual 0.8 instead of 1.6%. If Namin? is correct, the + value for wings give more than an usual armor because they spans across multiple slots.
Silk Robe trades massive physical defense for the slot and how it is invisible to other players. Flower Wings have a very high defense rating in both physical and magic, but it lacks the slot and allows people to attack/attempt status infliction without fear due to its visibility.
Certainly Namin? believes that flower wing is one of the best armor for PvM purposes though... at least in the old svn, Namin? can tank any biolab monster (as long as there is only one of them) with flower wing except for Power Up lv 5 + mammonite/bowling bash.
