Decent guide, but I'm kinda confused. Are you trying to build her as an AP carry or as a support? If AP carry get a Void Staff right after Raba, if support get CV and more support items please.

Well read i gave you my reason ^^

nice build similiar to the most builds but i rather use Force Glyphs's instead potency..

its also very nice if you got potency Quints because you got an nice output any time :D

AP Runes are to compensate that I go for a surviabilility + utility item first and Zhonya is put in the build at the top.. but if you had read the guide I put it into situational items.
3rd - You can always be at the edge of a fight.. but you still will get in fights with high mobility or fast ranged DPS characters like Ashe or MF who are Physical Damage Based.
Have you even tried the build before commenting ? and as I stated at the beginning this is not a bible.. its a guide.. its my way to build Orianna. Going FULL AP or AS/AP means weakening your supporting potential.

I don't think that Flat Runes for Ability Power are a good choice unless you're playing someone like Akali. Furthermore, Orianna doesn't need a Zhonya's Hourglass because she shouldn't even be near the middle of the fight anyway.