User blog comment:JBox2D/Diana Rework/@comment-25185372-20141015183801/@comment-24090662-20141015221917

You're turning a really simple ultimate into something incredibly complex and incredibly powerful. The point of this ultimate is that it's not actually that important to her combo: the cooldown and damage are low, and it's mainly supposed to be used for it's utility.

It's a large AoE vision denial, which also prevents allies of the affected units from seeing in, which makes it a better version of Graves's smokescreen in that respect. Then you've got minor damage which mainly just serves to add moonlight, which is both a reveal and lets you dash a lot. Basically, you use it in a teamfight so that you can use the enemy team as 'stepping stones' to get to your target and kill them, and you can also use it when going for an objective or something similar because of the vision denial. It's not supposed to be a game-changing high impact ultimate, just like her current ultimate isn't.