I have had some decent success with my Scum deck but it is not really 100% all about capture. I have found that Scum really shines when you use Tactics Icons to Exhaust Units and maybe every once in a while blow up an Objective. While the Capture mechanic can be really useful it is not 100% always going to happen the way you want it to. In response to the "Unblockables", Units like Sleuth Scouts and Blockade Runners, I have altered my deck towards having more low cost Units to defend with.
2x Jabba's Reach
2x The Tatooine Crash
2x The Trandoshan Terror
1x Jabba's Orders
1x Feeding the Pit
1x The Bespin Exchange
1x Hive of Scum and Villainy
While I must state there is a lack of Blast Damage in this deck, I must also mention that Scum and Villainy is not really an overly aggressive Affiliation. I actually tend to play them similar to Sith Control type decks. Build up a wall of Units, defend, only strike when it is most convenient, and while my opponent is doing things, mess with them. There is still a decent amount of Capture effects within this deck to prove useful.
Rebels: 3 X-Wing, 1 Y-Wing, 1 A-Wing, 1 B-Wing, 1 YT-1300
Imperials: 5 TIE/LN, 1 TIE/ADV, 1 TIE/IN, 1 Firespray-31