Based on using KotSF pregens, I can tell you there is a mountain of difference between Scale mail no shield, and platemail with shield. The Paladin with shield gets hit considerably less frequently. So much so most monsters just give up on attacking him, and go after the easier targets (except for his mark).
I intend to play a Dragonborn Warlord, and don't see any reason not to use a light shield. A two-handed weapon gives minimal advantage. My job is not to be a Striker, it's to be a Leader, and I feel my survival is more important to the party. I will also upgrade my armor to scale for a bit more survivability, and no skill check penalties. I'll be happy at AC 18, and happier when I find a Bashing Shield or Shield of Protection. I'll probably stick with the Light Shield because again, it has no skill check penalty, and makes it easier to pull out a potion and such.
I intend to play a Dragonborn Warlord, and don't see any reason not to use a light shield. A two-handed weapon gives minimal advantage. My job is not to be a Striker, it's to be a Leader, and I feel my survival is more important to the party. I will also upgrade my armor to scale for a bit more survivability, and no skill check penalties. I'll be happy at AC 18, and happier when I find a Bashing Shield or Shield of Protection. I'll probably stick with the Light Shield because again, it has no skill check penalty, and makes it easier to pull out a potion and such.