Carth is actually really strong. Use him if you want.
Any combo of Carth/Zaalbar/Jolee/Juhani/Canderous will likely do extremely well. Bastila/Mission/HK are okay but feel really gimped to other 5 and T3 is kinda a utility character that you can pretty much just trade out all the time.
If you do run Carth or Canderous... Care with your money, they needs a lot of it to be good. (Carth more so then Canderous. Good Swords are pretty much free. Good Blasters tend to cost money.) Also make sure to run Tatooine first. Better drops if you do it first.
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Whatever...