New player here, advice appreciated

STH (Stormtrooper Han) is a MUST at mid to high levels (unless you have Baze Malbus or Shoretrooper) for the TMU (Turn meter up) factor alone. Wedge is squishy and will die quickly but with STH he'll survive a lot longer. Farm STH over AA. AA is good mind you for leadership and cleansing but STH is a necessity in the beginning. STH needs a lot of speed to get going and sadly until you reach level 50 and open up mods he'll be rather slow...still, he's a darn good tank with a nice offensive kit. Just don't waste ability materials on his leadership ability - though not a bad ability (it's actually pretty nice) his other abilities take precedence.

Acrofales has also given you some darn good advice on how to counter a speedy STH. Boba's rework last month made him a speed demon without mods and a speed monster with them. He also can help you out tremendously in the credit heists as he is a scoundrel like STH. A good pairing would be Boba as leader with STH as your tank. Do you have other scoundrels available to do that mission because that's the #1 source for credits? If you don't, I'd suggest IG-88 (from Arena) and Cad Bane (from GW). Zam Wessell and Dengar are also good but are slightly rarer (Dengar from Chromium or Guild Shop and Zam from everywhere but never where you need her ;) )