I don't think it was necessarily laziness. Β It came down to using what they had in surplus, making them look more sci-fi but without impeding the function of the gun so that it could still fire blanks for the purpose of adding effects later. Β Plus, any mods they did had to be replicated easily, like with the Stormtrooper E-11. Β It's easier for us to modify things today since we have CNC machines and 3D printers, etc.
The blaster in the photo is just a repaint of the Nerf dart firing DL-44, which is a bit disproportionate to the movie prop since the Nerf version has to accommodate darts. Β I also added some cosmetic details to make the large surface area more interesting, but none of it is movie accurate. Β I do appreciate the feedback though π