Why Riven has her shield :)
This post isn't to say Riven is balanced, fair or well designed. Those are different topics. It is merely addressing one aspect of her kit top laners complain about a lot.
Her shield.
Riven has her shield because she is a melee damage dealer, all melee damage dealers barring assassins have some form of defensive steroid or fight sustain, this allows them to trade in lane without it being a total loss, and team fight without dying before they get in range to do their job.
Riven has: Mid tier base HP for a top laner. Mid Tier HP per level for a top laner. The 6th lowest HP regen in the game(this one is important). The 4th lowest HP regen per level in the game(this one is important). Bottom 1/3rd of champions for base AD. Bottom 1/3rd of champions for base AD per level. Bottom 20 for attack speed. 7th highest attack speed for level(because she builds none). Middle tier Armor and Bottom 1/rd Armor per level for a top laner. Above Average MR and MR per level(for trading against top mages).
Here is the important thing when talking about Riven's shield: The 6th lowest HP regen in the game(this one is important). The 4th lowest HP regen per level in the game(this one is important).
Her other defensive stats are about average, but this one is utter garbage. Almost as bad as poor Mordekaiser. Riven has no other form of sustain in her kit either. If Riven goes in for a trade against any laner with sustain, and comes out behind or even cuts even with them, that is a lost trade for her, as she must either burn a pot or wait for regen. In fact at level 1 it would take Riven 1.5 minutes to regenerate 100 HP. Which can be done by other top laners in between 10-40 seconds depending on their kit sustain and HP regen.
Outside of Laning, Riven has no other defensive steroid. If we compare her to her peers who are melees that have to dive in and deal damage. Her shield does not compare to Juggernaut steroids or tank steroids. Riven is a Skirmisher. Other people in her class are Ekko, who has a huge shield plus his ult. Fiora, who has her passive healing and her parry. Yasuo, who has his shield and windwall. Yi who has his W. Trynd who has his ult and Q. Jax who has his dodge. All Skirmishers have a defensive steroid, usually that has some skill and planning involved in it's use, and allows them to survive team fighting and laning. Riven is no different.
Those who insist her shield is 'cancer' and must be removed. Must also want all of these champions to lose their defensive steroids. Otherwise they are being hypocritical.
With respect for the positive end of the community - level7rovinonetrickboxboxlcs.