Ya the AD build hasn't worked for me but in a few bot games, i really don't see anyone pulling it off nor it being actually a viable build, im actually going go ahead and remove it.

masteries ive been choosing lately haven't been standard by any means, usually trying to make bruisers out of some champions and after using diana in many different ways ive kinda found she really just fits a mage class more and more. Just doesn't have the defense to sustain herself against the meta. Alot of that factors into the decrease in spell vamp from AOE abilities, since everything she has is AOE based she takes that hit to vamp unless she can hit a large crowd.

Interesting item choice. I suggest you make commenting necessary to vote, so you can see people's criticism and improve. I think your mastery choices are rather strange, and AD diana doesn't really work, but other than that, its a pretty good build.