"Only Imperial Stormtroopers are so precise" jokes aside, I can kind of get the Stormtrooper Precise ability and Surge-to-hit conversion. They're (theoretically) trained troopers and should be pretty lethal. I can maybe even buy the white die for the E-11 vs the black die for the Rebel rifle on the theory that the rifle is more powerful than the standard issue carbine.
I can even buy the "Nimble" trait for the Rebel Troopers, since they're in shirtsleeves, not weighted down by armor, and able to dodge.
But why do Rebel troopers have the defensive surge-to-block conversion when it's the Stormtroopers wearing armor? Shouldn't, maybe, I don't know, the two surge conversions for the two units be reversed?