Go Operative + Sniper. Neither of smugler classes are even remotely as cool as Imperial Agents.
sucker punch, dirty kick, shotgun, double pistols, these all are inferior to their mirror variants.
Sniper has little variance in attack animations. it's just aim rifle=>fire, aim=>fire, send attack drone, fire, while Gunslinger has all fun "gun kata" dual blaster stances, the finisher looks a bit more fun (two massive energy bolts with thick smoke trails are plain BA), etc, etc.
Don't bring two pistols into a sniper rifle fight. Sniper has the same vibroknife animations as operative. Sniper rifle series of shots (quickshots) is simply amazing, the way explosive probe is placed on enemies is great as well.
A guy with pistols is more supposed to be a run and gun style, not standing in one place like sniper does.