I have been running a list with all three of your favorites. I'm not sure it's top-tier, but I win more than I lose with it, at least. I'll run through my thought process for each of the cards.
Deployment Cards: Bossk (8) -- The archetype for the list: Hunter/Brawler. There aren't a ton of dudes that can wipe out Han Solo (+ Brace for Impact) before he gets to return fire. Plus, his little lizard ears are almost certainly the best detail on any model. Maul (7) -- He's in this list to be a menace... a Phantom Menace. That is, to run in, probably kill one guy, and then get chopped in half.
elite Weequay Pirate (7) -- I mean, this is a mercenary list, is it not?
elite Clawdite Shapeshifter (6) -- You're right that the rebel care package is better support for 6 points, but I like this guy's ability to switch to dealing Weequay-esque ranged attacks or Obi-wan-esque pseudo-melee attacks after round 1. He's not the best support and not the best attacker, but he can do both. Jabba the Hutt (6) -- In the first round, he's essentially just an extra command card and a focus on Greedo. In subsequent rounds, he's a command card (from Black Market) and an extra attack with someone like Bossk or Maul. Plus, he's a usually-safe place to attach Indentured Jester. You could take the rebel care package instead, but then you don't get to make the low, rumbly chuckle at your opponent when you make a good play. Greedo (4) -- GIA, as has been discussed. Black Market (1) -- With so many strong command cards, I want to see them all. Indentured Jester (1) -- People forget Salacious B. Crumb is a brawler until he scurries up and does 4 unblockable damage to someone with Swipe, Scratch, and Grisly Contest. People don't usually even bother killing him, but if they do, they have to kill Jabba too to get his point.
Command Cards: Assassinate -- Opponent gets 3 extra damage and a helping of salt. Comm Disruption -- I decided to take this instead of Negation because (a) I had the extra point left, and (b) now I can negate my opponent's negation (since the list has 1 spy). Ha-ha! Might be worth just taking both. Element of Surprise -- The elite Clawdite can snipe someone like C-3PO and make sure he won't dodge. Fleet Footed -- Movement is preeetty nice for brawlers. Or you never know when it'll be useful for someone else. Grisly Contest -- Two unblockable damage from Maul, Bossk, or Salacious that can be used to finish something off. Bossk can potentially recover the two strain-damage at the end of the round, too. Heightened Reflexes -- Standard hunter damage card. The anti-dodge. Intelligence Leak -- It's so much fun getting rid of my opponent's Blaze of Glory or Son of Skywalker. Looking for a Fight -- It's a better Fleet Footed for brawlers. If Bossk or Maul don't need that extra movement point, they can instead attack and then use this to shove an enemy and trigger Parting Blow. Opportunistic -- This is great for getting Bossk and or Maul into position before they activate (or getting them back to a safe spot afterward). It works for any mercenary, but positioning those two is most important. Parting Blow -- Extra attacks are cool. If Bossk uses it, he can shrug off the stun at the end of the round, too. Planning -- These other cards look nice, let's get them all. Positioning Advantage -- We're all in on damage at this point; might as well follow through. Primary Target -- The lack of the rebel care package means a general lack of focus tokens. This helps. Take Initiative -- Hard not to take this card. Then there's the cool interaction with Maul's Sustained by Rage ability. Tools for the Job -- See Figure 1 above.