There was word a couple months ago from the showrunner that there'd be no easter eggs/fan service in this show. I have a love/hate relationship with that stuff. I have fun with it like anyone, while also being irritated sometimes when it is gratuitous. And when I read the detail of what the showrunner said, he was essentially on board with me. Obviously we already knew Mon Mothma was going to show up and that is the sort of thing some people would relate to this. But his point was that if they showed anything you'd seen before it would be for a really good reason that was important to their story.
Saw Gererra is sort of his character. He didn't make up the name, but when he showed up in Rogue One is was pretty much pure Easter Egg. There's little to connect one to the other except to make a hard reference to Clone Wars. While the characters having little to connect them beyond the name can be forgiven for the 20some years intervening, it is still a fact. He can say today, sorta, that this doesn't count because it was his own character like Cassian and he is continuing his own story (in reverse). But what I'm getting at through all that complicated preambe is that I enjoyed the scene with Saw, but it doesn't look at this point like it was anything other than, "Hey remember Saw?" as far as THIS story goes. Was that it, one and done?
Maybe he'll be back for the finale or more prominent in season 2.
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I appreciate development of the idea that at least at this time period the good guy/bad guys lines are being blurred. In OT the good guys were the Rebellion and the bad guys were the Empire. In PT the good guys were the Republic and the bad guys were the Separatists. But Cassian can't really tell the Republic and the Empire apart. That's in keeping with speculation that had been done to cover his misstatement(??) in Rogue One that he'd been fighting these guys since he was a kid when he was too old to have grown up in the Empire. Mon Mothma sticks up for Separatist Do-Gooders. I don't have anyone in mind and maybe there's no one to grab, but it would be nice if they could pick up a sympathetic separatist character from Clone Wars and drop them into the Rebellion now. It would be more poignant than Saw.