In the original movie we see them devastate the rebels when capturing the ship. We see Obi-Wan mention that the shots on the jawa transport are too accurate for sand people so they must be Imperial. We see a lot of missed shots as they escape, but as you said and as Leia herself noted, they got away far too easily.
And then there’s Rogue One/Andor that shows the true side. Andor kicked scary up a notch for even the base stormtrooper.




Great additions. And the biggest Imperial vulnerability remained the same as it had always been throughout. Cassian points this out in an early episode - they’re so full of themselves being the Empire that you can just walk in if you blend in. They can’t imagine someone having the balls to do that. Even in late RotJ we see that, the trick to open the door to the shield control. Of course someone with a walker is going to be them, telling them to open up. Who else could it be? Arrogant to the end. Hell, Palpatine at that point, even after him devising this plan for so long and right under the Jedi, is so proud and sure of himself at the end. He has foreseen it all, and how could these rebel insects win now?
And I mean he’s almost right. He’s just not paying attention to minor details.