Riven's Shield.
Why is Riven the only champion allowed to have a shield that scales with AD? You choose to make Mordekaiser's shield scale with his level because having it scale with damage was too much - isn't this basically the same thing? She can literally 1v1 most champions with more hp than she started with, between her shield and the lifesteal she builds. For the love of Faker, make her shield scale with AP like with 90% of all other shields.