I prefer playing fighter/bruiser/off-tank Diana rather to assassin Diana
I usually build her as an off-tank and a good amount of ability power, usually items that provide both. I like the survivablity that the build provides, you don't get instantly blown up like how assassin Diana does due to you just building damage. Diana's supposed to be a fighter anyway. I also feel like it adds onto the thematic aspect of her, diligent fighter who doesn't give up instead of an assassin, I don't really see that as part of her character.