Is Riven even actually that strong?
Keep in mind this probably doesn't apply to High Elo Riven mains who could overcome counterplay and counterpicks or Bronze/Silver (maybe even low gold) Elo because even the most cheese champions can be effective there.
I feel as though she's only becoming an issue because people are too busy spamming 'OMG Riven noob OP champ all you have to do is button mash' to realize she has a plethora of counters, very simple counterplay, AND WE'RE IN A F*CKING TANK META FFS.
Not only can she not actually get to your back line of champions, but she's far from Top Tier in terms of peeling for carries in comparison to the large sum of dominant Tanks present in the current meta.
The only time Riven is an issue is when you put yourself in a risky scenario as a squishy or isolated champion. If you don't try to fight her during her power spikes (from either items or levels), avoid unwarded jungle (especially if the Riven is mia), and if you pick champions with meaningful and reliable AoE or point-and-click Hard CC THEN YOU'LL BE PERFECTLY FINE.
Riven is only an effective champion if she snowballs early or if you allow a skirmishing team composition to skirmish. Wait out her power spikes and/or prevent/delay them entirely. In a Tank meta, picking Riven makes your team lack tankiness comparatively and makes itemizing again AD and Attack Speed all the more appealing.