I don't think that's a good solution. Have you even looked at Riven's win rate in games under 25 minutes?
https://champion.gg/champion/Riven/Top
That's right, 49.07%
Riven's win rate doesn't spike until late game, at 30+ minutes in, because she's an item reliant champion. Don't get me wrong, all champions need items, but Riven specifically needs items because she doesn't have great base damage on any of her abilities. Her passive is a percentage deal, which is based from her bonus AD, and all of her spells are also based on scalings more than her base damages.
Riven is designed to specifically be a late game champion, and that's exactly why her win rate is always high. When Riven makes it to late game, she does what she's supposed to do. I personally can't understand why no one understands this. Riven's early game is terrible, people who are claiming otherwise are blaspheming because she has shit base damages, shit scaling, and the only good thing she has going for her is the mid range cooldown on her shield to help her survive in lane.
The players who beat you out early on Riven are just better than you at the game. That's plain and simple. It wasn't because they had an overpowered champion, it was because they outplayed you or simply had more help from their team. Early match Riven is worse than almost every Top in the game in terms of base damage and scaling. She doesn't straight win 1v1, without having poked the enemy down or made some great decisions. Understanding what to do is a part of the game too, that's what most people on these boards can't comprehend.
99% of these players on the boards are all about that "fight me bro" mentality, run it down mid game play style, and can't comprehend how to deal with champions that counter that. That's precisely what Riven is good at. She's a champion designed to stall into mid and late game against aggressive champions that just want to fight you and kill you, which is what people don't like.
At any rate, I'm just some noob who only plays ARAM's so my word doesn't mean much. I gave up on ranked in this game last year, so not sure how much I really care about what anyone on these boards thinks.