The first Galactic Republic wrote:I wish more EU writers, canon and legends, would have focused on Separatist characters and war material becoming involved with the Rebellion. I imagine people unhappy with the Republic wouldn’t have liked the Empire any better. It’d be cool to see some Separatist commanders with the Rebels. Imagine Alliance droidekas, AATs, and Providence Class cruisers.
This happened to some extent, but not much. That Rebels episode where they meet Kalani is the most we’ve ever gotten.
That's because the droid armies were shut down and scrapped. And the corporate entities that made up the CIS were disassembled.
You might get some people involved in the rebellion, but the Droid armies are no more.