i feel like everyone is forgetting a nasty Interceptor pilot by the name of Canor Jax. Get him into the middle of your enemy's formation, and they're gonna have a bad time, and god forbid he ends up in someone's rear arc at range one. Granted it takes skill to get him that close and have him survive, but it's certainly doable. I can see him having some decent synergy with a mini-Howlruner Swarm, particularly against lower Agility ships.
That all being said, I feel like a lot of the frustration at the Rebels' synergies (in this and other threads) boils down to the game's asymmetric faction design, which IMO does a good job keeping with the lore of the Star Wars Universe. The Empire lacks synergies because, as I see things, they rely more on their superior numbers. "Quantity has a quality all its own," and all that. The Rebels can't afford to play that game, so they work as a group to take out a numerically superior force. That is probably why we see more of their strategy reflected by the game mechanics, and the Empire has theirs reflected by their lower priced pilots, particularly with EPTs. And on the flip side their better pilots are better because they have to be more individually focused and skilled to survive against their (arguably) technologically superior opponents.
I will certainly concede the point though that the Empire is lacking in Unique crew specifically, though I feel that the Rebel Prisoner is being undervalued. It stops Opportunist, provided the first ship shooting has it, and even if it doesn't that's a ship that's going to have to do a green next turn if they want their action. As for more, I think we'll have to wait and see what Huge Ships drop for the Empire. I expect they'll even things out a bit.