#just...make them believable

Freaking World Devastators.

To those unfamiliar with them, they are giant mobile factories that have a giant vacuum cleaner stuck to the front of them. They pull up anything in their path, break down the materials to molecular levels, and reform them into raw materials that are then processed on assembly lines to become new weapons and ships. 

They are so 100% Star Wars. 

But they were, tragically, in the Dark Empire comic books, which also featured a resurrected Emperor, Luke going evil, and a complete return to Status Quo (it was kind of The Force Awakens before The Force Awakens). But the true flaw of the World Devastators was this line:

It reeked of “well we have to make sure the readers are overwhelmed by this” and was also a blatant lie. If Palpatine had just built a Death Star Mon Calamari would have been blown up in seconds. Furthermore, the Devastators were given Completely Unbreakable Shields and Unstoppable Weapons so yeah there’s Nothing You Can Do About It and...

That’s bad writing.

The concept of a World Devastator is simple, and could have easily been used throughout the rest of the Star Wars universe. Honestly, they’re weapons that I would have expected to appear in The Clone Wars: they’re just mobile factories, after all. No one would ask “Well, why didn’t they send a World Devastator to Hoth?”, because the slow-moving factory weapon would be far less effective than an onslaught of Star Destroyers and ground forces.

Look at their designs, too. They are so beautifully constructed in their hideousness--they look like objects that have been cobbled together from model kits, like something you would see in an old Sci-Fi show. They’re not quite Ridley Scott or Gene Roddenberry, and not necessarily George Lucas, but they have a beautiful appearance of “The Industrial Revolution Went Horribly Right Also Aliens”.

Sadly, I wouldn’t imagine that such a weapon would appear in Rebels--the galaxy is mostly under Imperial rule, so they have the worlds they need to produce raw materials. At the same time, the Empire doesn’t like to play by the rules, and it has shown a constant obsession with harvesting raw materials and fueling its expansion...so maybe they’ll show up in Season 4? 

Obviously they would have to be refined in their nature and toned back, but tell me you can’t imagine a squadron of Y-wings swooping down on one of these things as it eats a forest, dropping their bombs as they navigate a storm of surface-mounted laserfire. It would be so easy to imagine General Grievous utilizing these to pick a Republic planet clean in order to manufacture ten thousand battle droids in a matter of minutes, and to see clones rappelling down the side to infiltrate the behemoth and bring it down from within.