Fox-Fire is more useful that just to help farm. It can be used after you land Charm and it often deals more damage than Orb of Deception. It is also good to use when using Spirit Rush to deal more missile damage.

BTW my guide already has this name.

a few advices to make your build better,when you have time add icons to everything,items skills spells!
Also I've said in other guides as well but you can add Mejai Soulstealer as an alternative item,if you are skilled and manage to stay alive,Mejai is the best replacement for Morello.
Mercury's Boots are the best alternative if you are being focused.
You might want to add a laning phase paragraph too! Ahri has soo many potenitals in al the lanes! That's all for now ^^