It's not just ratios, but base values as well. Vayne and Mundo have virtually no ratios, but they scale heavily from base values
The reason why I suspect they're going to be bullshit is a combination of several factors. One, the adc's passive is spray and pray type of penetration on her autos, which means incredibly lane pushing and strong aoe output in teamfights. Two, she has access to slows and snares as basic abilities, one of which activates off the results of the slows and the autos, so it's hard to avoid her. Finally, her ult not only makes her invulnerable during cast, but she can move and setup a large aoe snare with it. Regardless of scaling, that ability to both push waves and provide large amounts of cc is extremely valuable.
On the support's end, his passive is Malphite passive basically, but he has access to a slightly delayed Malphite ult as a basic ability. He also has a poke spell that provides an aoe heal around him that can be activated early by a teammate walking into the area. He has a leesin style of shield, which can be cancelled mid flight by said mini-Malphite ult. And his R is basically Kennen's E with a slow attached. First off, let's just appreciate the bullshit of a Malphite ult as a basic ability, and the fact that it is in a kit that already has another dash in it, meaning he can pretty much Malphite ult you from across the screen. Second, despite the hard engage abilities, he has access to a form of sustain, which was literally the reason Alistar was reworked (which is hella ironic, because this guy is basically old Alistar on steroids). Lastly, he's a support, so his ratios are largely unimportant, and his utility is all that matters. With a low CD short range shield dash that can be a longer range, longer CD shield dash, a malphite ult on a basic ability, a poke that heals, and an aoe follow up on his Malphite engage with his R, his ratios can be virtually non-existent and he'd be fine.
So ya. They're going to be broken.