Darius has many things going for him, which is why I like him. He has great damage, sustains, zoning, scaling threat, and a really scary presence if not dealt with during fights. However, he's right next to illaoi and mordekaiser in terms of kite susceptibility. Properly kiting him or cc chaining him renders him nearly useless. However, champions who orb walk, like say riven, might find it more difficult to face darius.
Correct, I am a darius main, and I stand at a nice winrate with him, IMO. I know his strengths and weaknesses, and his few weaknesses render him so useless in many cases that he isn't seen much the higher you climb. RIven is seen however, because her weakneses are nullified by her strengths. I would assume you know this, as you have 74 riven games under your belt. Playing safer would make this suggestion of nerfing her shield useless, but seeing the 49% winrate you have on her, I would assume you play more aggressive.
Some things to note about darius:
*While he does have true damage, his rank 1 ultimate isn't a reliable damage source, so many trades with other champions actually turn out poorly for darius if he keeps going ham. level 11 is when his true damage really matters. Play darius a bit, you'll see what I mean.
*If the enemy ranged, be it mid or ADC, gets fed, darius can do jack about it if the enemy is smart.
*Darius's sustain has a delay, and can be flashed out of, or dashed out of. It's honestly mainly useful when the enemy huddles around darius.
*Darius has some of the lowest attack speed in the game. Even if darius animation cancels and does a perfect combo, he will get 4 stacks maximum. If the enemy walks away, Darius really can't do much about that.
*Darius has mana, and honestly, this mana pool runs out fast if not managed responsibly. The more aggressive darius gets in lane, the sooner he has to leave, in risk of the jungler.
The only reason I see you might have to complain about darius is if you struggled against him. Which is strange, because statistically, riven vs darius is a pretty solid skill matchup, though favored on darius, I have lost a few times against really skilled rivens. If you're amazing with riven (though your WR suggests otherwise), why complain?