User blog comment:Simbey/Real Talk: Riven/@comment-4952847-20140117233412

I think giving her mana is going to be a risky nerf. Riven is very reliant on her hyper agressive playstyle because she kinda has no other option. Her whole kit is damage + damage + mobility and whatever was left of her sliver of innate tankiness was nerfed to nothing. Now, her damage + damage + mobility ALL derive from her active skills, unlike some other top laners whose active skills are less relevant thanks to some passive components that make their auto attacks their main DPS.

What I am getting at, is that Riven becomes a sitting duck without her active skills. Her auto attacks are very standard and really, no threat once she's OOM. Whereas champions like Xin Zhao or Jax are still able to thrive without mana because they have passives that boost their AAs.

I am not saying Riven is 100% fine (even though I admit I don't see her as much of a problem at this stage either), I'm just saying that mana is not an elegant solution, because there is actually no other champion who is at 0% power when OOM, but Riven will be if she's got a mana pool.