So I have been playing Diana a lot recently(mid for anyone who cares) and whilst I loved every second of it because of the huge snowball potential that she has, there was a thought that struck me. Diana is an assassin that has a way to get in but no way to get out(similar to irelia). So then it struck me. What if we try to play Diana as a...
Bruiser similar to Irelia. There are a few reasons why this could potentially work.
1)Diana's passive gives her 20% bonus attack speed and an empowered auto attack on the 3 strike. As an assassin this may be used once max during a trade in lane but usually you don't really use it. This has great synergy with guinsoo's rageblade which allows you to proc the passive every 2 auto's.
2)Diana's base health(if coupled with scaling health) is actually pretty high so you don't need to build that much health to be tanky.
3)Her w shield is actually really good if you use it on champions. This is usually done by jumping in really deep. The tankyness would allow you to survive and proc the shield and deal a lot of damage in the process.
So the build would be something as follows.
Masteries you can go fervor of battle(for the onhit damage) or thunderlords if you want the burst. First item would be a rod of ages since it synergizes with Diana's kit very well, tankyness and damage. Then you would go into wit's end for the attack speed and MR then Ninja tabi's or mercury treads.Then you would go guinsoo's and at that point 1v1ing you would be really difficult because of the health and raw damage you have on extended trades. Then you would go tanky with an iceborn gauntlet and spirit visage.
So to conclude
-Rod of ages
-ninja tabi's or mercury treads
Iceborn gauntlet or an armor item
Again this is a very unorthodox sort of build and it's not guaranteed to be good however if you want to have some fun in a normal game or something like that I would highly suggest you give this a shot