Lately I've seeing a lot of threads claiming either that Riven is OP or that she is very good.

Riven is my favorite character so naturally, this is something for me to be happy about.

That having been said, I'm having trouble figuring out exactly where she fits. Perhaps this has to do with my team and how they view her, but it seems like Riven is a really well rounded character that can fit many different roles but is outstripped in most of them by more specialized characters.

Solo Top: Why not just play Irelia?

Jungle: Why not just play Lee Sin?

AD Carry: Why not play a ranged character?

Babysitter: Play a support character.

I really want to find a reason to use Riven more, I just feel like there's usually someone else who can do the job better. What am I missing?

That Riven is hot.

That's the main problem with balanced characters. They can play everything, mainly well, but simply because they can do that, other characters orientated to more situational roles are better.

If, say, you had an AD carry, a support, an AP mid, a jungler, and you were all solid players, you could easily pick Riven to fill in the gap and play all of those roles at once, to an extent.

Considering she excels at fighting more than one person, she would be a large benefactor in a teamfight, but even then she may not be the *best* pick.

I play her a good bit too and i have to say shes a great skirmisher and if you can out level the jungle you can start to counter them early being as you have a stun and knock up that can be set off one right after the other. Shes also great for using as an off tanky fighter,not something i usualy do but if you can grab boots, BT, Warmogs, Black cleaver, Randuins omen,and then either a frozen mallet or Phantom dancer you can easily out last and damage most champs i see though most people will probably tell you otherwise

I think it's more that the skill of her player isn't the sole determiner of how well she combos. Most of the claims that she is OP comes from a team composition that can't break her out of a combo, or hit a burst right as her shield goes down. A well played Riven can have continuous sustainability right in the middle of a fight, but the skillcap goes up for the champion fighting her as there are certain points in her combo to do damage or deliver a stun.

Riven is good at what she does, and what she does is hang around in the middle of a fight and not be particularly fast to die, and spread that damage around rather than getting one champ at a time.

Riven Autowins top against non-sustainers.
Riven Jungler doesn't insta lose against enemies with flash and she is much more confusing.
Riven Babysitter is like Poppy. Facecheck>instawin.

just solo top with her, thats her best spot and probably the only legit spot she belongs