Riven wouldn't be as bad to face if her early game cooldowns were truly punishable
Especially when it comes to top lane, one of the most important things you can and should learn is to punish misuse of enemy cooldowns. For a champion with so much damage, her cooldowns are really forgiving and her build path just adds salt to the wound. I know it's FOTM to hate Tryndamere rn but I would rather face a Trynd than a Riven any day of the week. Even a decent Riven is hard to punish especially if you're also playing a melee champion.
(And yes I have I know Trynd games in my history, just couldn't win with champions that I truly like and am taking time to really learn all I can before playing more ranked.)