Board Thread:League of Legends discussion/@comment-28704582-20160609224817/@comment-29639815-20160815051623

It's so she doesn't get instagibbed when commiting to an all-in. Her shield is designed to take one large instance of damage late game around 500 or so if you build her correctly. That's like 1 spell from a burst mage in a 1.5 second window that will be refreshed 3.5 later (with maximum CDR) which gives plently of room to blow her the fuck up in a lategame teamfight. You could nerf the ratio but that would significantly hurt Riven's lategame carry potential. Which doesn't make sense considering she's a carry champion that's meant to scale the longer the game goes on (who would've thought?).