Everyone screams the shield is OP for ADC, but it's not really strong, it's actually weaker. We lost the 12% damage reduction and got a shield added. Yes for some the shield value is fairly big(240-600) scaling from levels 9 to 18 . However when we look at Maw of Malmortius it grant a flat shield that absord 350 magic damage but also have a flat 55 magic resist alongside the shield so the value remain good and it also reduce damage from every source.
So they made the PD shield bigger because of no resitance paired with the item so the shield got bigger. However, Maw shield last 5 second(same for hexdrinker shield) but Phantom dancer shield last only **2 second**.. it's way to short to be really useful and any valuable. Right now I would still prefer to get Maw over PD because the main reason it's better is because it provide resistance alongside. I would get Phantom dancer against AD team as the shield can be helpful but the duration is too short to even be good so I might as well pick a GA instead. All for to get the point, standarize the Phantom dancer shield to 5 second as it is on Maw.